How much time and effort may have been put in?

[RobGea]

I wonder though: is the idea of a medieval "hobbyist" spending an unlimited amount of time and effort on a passion project really feasible without religious fervor? Any pre-renaissance examples that we know of?

If Igor the peasant farmer worked from dawn till dusk then in an hour of evening firelight whilst his wife cooked dinner,
Igor whittled wooden caricatures of local personalities, he did this most nights from his twenties till his fifties[1],
say 5hrs per week for 30yrs thats 7,800 hours of 'hobbyism'.
If it took 20 hrs to make a complete figure that 390 figures that Igor created in his lifetime.
As soon as Igors collection is broken up then very little evidence remains that show these sculptures were the lifetimes work of one man.

The Villa of the Papryi is some rich persons collection of statues and scrolls, how much time and money were invested into creating that collection we will never know,
but if it were not for a volcano, we would never know that that person collected anything at all.

TL;DR Hobbies dont leave much evidence.

[1]https://historymedieval.com/medieval-england-lifespans-how-long-did-people-really-live/
[2]https://en.wikipedia.org/wiki/Villa_of_the_Papyri