There is no easy, short answer here, but here are some key points:
- Even in ancient times, humans did keep extensive records in some regions/cultures; in fact, there is evidence to suggest that record keeping pre-dates the development of writing.
- The extent to which records have been kept has depended on a host of factors, among them the development of states, religion (which has both helped and hindered the keeping of records), literacy / education / knowledge / technology, political stability, economic prosperity, etc.
- As noted in other answers, many records have simply not survived, but this has not always been due to a lack of effort or perception that something should be preserved for posterity. We have lost many potentially invaluable records while some more 'mundane' ones have survived.
- Records have been lost for several reasons, among them: neglect (i.e. little or no effort to preserve), accident, collateral damage during invasions, deterioration of materials over time. J. Raven (ed), Lost Libraries, makes for sober reading.
- You mention "writing down how something was repaired". There were such texts but, mostly, such knowledge was passed on down from father/mother to son/daughter, from master to apprentice. We tend to create and preserve what we need before anything else, but some things simply weren't needed - the master was the record of 'how to do'.
- Identifying one particular time when there was a 'change in mindset' is, in practice, impossible. Records have been diligently compiled and preserved at many points in time in different regions of the world. The difference between modern times and pre-modern times is that record-keeping is now much more widespread, in large part because of the increased number of highly developed states (primarily for the reasons stated above and elaborated on below).
Record keeping is as old as or older than writing itself; the earliest evidence we have of writing suggests that it was used to keep records. Some ancient writers (e.g. Herodotus, Polybius, Xenophon, Sun Tzu) clearly intended to educate and instruct both their own and future generations, and the copying of their works through the ages shows that some people at least saw value in preserving them.
Also, where you have bureaucrats you have records, and bureaucrats have been around for a very long time (see, for example, China). Much of what they recorded was fairly mundane so our 'mania' for keeping detailed records is certainly nothing new, though many of these 'mundane' records have survived more by chance or accident than by design.
The keeping of records is very much tied up with the development of the state (and its accompanying bureaucracy), which in turn both necessitates and facilitates the keeping of records. The states of today generally have far greater resources and needs for keeping and maintaining records than they did a couple of centuries ago. This is one possible point which "inspired this change in mindset", but keep in mind that there have probably always been people who sought to preserve for future generations (if only through family inheritance at first), and there will always be people who see no value in preserving something (or who set out to purposefully destroy, e.g. the Taliban's destruction of the Buddhas of Bamyan).
Although there is evidence of many 'mundane' records being stored, how long the creators intended them to be kept is hard to say. The most likely answer is 'for as long as they thought them useful'. Perceptions of usefulness, and thus the desire to record, catalog and preserve, can change very quickly. For example, as recently as the 1950s, many saw little point in preserving for future generations old films or TV shows; although they were sometimes stored, it was usually in a haphazard manner with little regard for preservation. Hence the destruction during WWI of most of the films of Georges Méliès (a collection which would now be priceless) and the loss of early BBC TV shows from the mid 1950s such as some of the classic Hancock's Half Hour - the tapes were simply wiped so they could used again. Thus, there are clear examples of both meticulous record-keeping and of non-preservation from both ancient and modern times.
A key depository of records is the archive, the existence and maintenance of which is greatly facilitated by the existence of a stable, prosperous state. Archives date back to early ancient history, and they existed in ancient Greece and Rome. However,
These archives were all destroyed during the Great Invasions of the
fifth, sixth, and seventh centuries A.D...
Source: Michel Duchein, 'The History of European Archives and the Development of the Archival Profession in Europe'. In 'The American Archivist Vol. 55, No. 1' (1992)
European archives began to revive only in the eleventh and twelfth
centuries when a new political and religious organization of the
continent gradually emerged from the chaos....All the new monarchies (German, French, English, and later Spanish), the great feudal powers, the Church, and the towns organized their own records-keeping independently so that little by little local or national traditions and methods were created, giving birth in modern times to the various archival systems which now exist.
The above, of course, only applies to Europe; the extent of record keeping has varied greatly throughout history in different regions.
Knowledge and technology are also key factors. Knowledge may bring realisation of the importance of preserving something, while technology helps us to achieve the exploitation and preservation of a record.
Below are a few examples of record keeping or instruction materials for posterity from Europe and Asia for you to explore further:
In Sumeria, Cuneiform was used to keep records of everyday transactions. From circa. 3500 BC, "clay tokens were used to record specific amounts of livestock or commodities." The article The Evolution of Writing has much more on Sumerian record-keeping.
The Ancient Egyptians kept records and had histories. The freely available article Ancient Egypt: The Development of Record Keeping in the “Old Kingdom” has details.
From at least 1450 BC the Linear B script was used by the Mycenaeans to record wool, sheep and grain disbursements by cities, among other things. Some of these records on clay tablets were stored on shelves.
There are many examples from ancient China and the Hundred Schools of Thought of texts intended for instruction, covering behaviour (e.g. Confucianism), military science, administrative methods etc. Not least of these is The Art of War, attributed to Sun Tzu.
One of the most famous examples of record-keeping is the Greeks recording of the the winners of the various events at the ancient Olympic Games. Herodotus stated at the beginning of Histories that he wrote because:
so the memory of the past may not be blotted out
from among men by time, and that great and marvellous deeds done by
Greeks and foreigners and especially the reason why they warred
against each other may not lack renown.
Xenophon wrote several 'instructional' works, among them On Horsemanship and Cynegeticus (hunting with dogs), though whether he intended them for future generations as well as his own generation is hard to say.
The Romans had official records offices, the best known of which is the Tabularium in Rome. Unfortunately, everything has been lost to time. Not lost, though, is Pliny the Younger's description of the disaster that destroyed Pompeii and Herculaneum in 79 AD.
- Plutarch's Lives of the Noble Greeks and Romans consists of a series of biographies of well-known Greek and Roman figures (though some such as Lycurgus are "quasi-legendary"
Polybius noted in his Histories the importance of the study of history for a life in politics, adding that the:
surest and indeed the only method of learning how to bear bravely the
vicissitudes of fortune, is to recall the calamities of others.
The 10th century AD The Complete Book of the Medical Art by the Persian physician 'Ali ibn al-'Abbas al-Majusi includes a 'how to do' of surgery, and much more. It "was widely circulated in Europe" after being partially translated into Latin in 1089.
In medieval times, England was one of many states that kept records. For example, the Pipe rolls are detailed financial records of the treasury which date back to 1130 and the reign of Henry I. Detailed legal records also survive, kept in what are now known as Year Books dating from at least 1268. And, as mentioned by justCal in a comment, let's not forget the Domesday Book which has a long history of use.
J. Raven, 'Lost Libraries: The Destruction of Great Book Collections Since Antiquity' (2004)
Recordkeeping and History
Rochelle Forrester, 'History of Writing and Record Keeping' (2016, revised 2019)