Just something Ive been pondering as Ive been beaten by quads twice and a better boat in recent succession, which got me thinking should I be taking more care when I hit the full house?

I guess for example there must be some numbers somewhere that shows how often you run into quads when holding a full house..

If your only holding a boat due to your pocket pair (lets say 77+) should I be more cautious than I currently am?
I would find more folds if I had 22-66 facing an aggressive river bet but thats down to considering higher pocket pairs could easily be there.

But I don't think anyone can easily (if ever) really fold a full house..

I have folded the FH a couple times and it turned out to be the right call. Both times I had the FH with the lower set and my opponent had the same with the higher set.

Stack sizes? Betting action? Board texture?

It's pretty hard to fold a full house, but given the right combination of the above, it could happen. With 100xbb stacks (and hold'em), I am having trouble thinking of what board or action would make me do it.

It's not too uncommon to be correct to fold a full house. Against a tight opponent who raises/bets big at the river with deep stacks, you would usually have a clear fold in situations such as:

** Holding KQ on 555 A A
** Holding JT on K T 777
** Holding Q7 on AAQ Q 5

If you restrict to situations where the board has a single pair and you make a full house using both hole cards, it's very rare (being correct to fold your full house) but still happens occasionally in very tight-range situations.