Fair additional point about having to spend time/mental energy on dealing with the oil disposal. Not a criticism, though - I'm very much in the same 'place' as

Fair additional point about having to spend time/mental energy on dealing with the oil disposal. Not a criticism, though - I'm very much in the same 'place' as you - trying to find a better balance of what to do myself vs. outsource... and I fear I often get the balance wrong, on the side of not outsourcing enough. Case in point: I recently changed my GF's car wheels, over to the winter wheel/tyre set. Ahead of time, it's an easy calculation: a few minutes per wheel (I've got good tools including an impact wrench already) saves her a decent amount of money, plus the time to/from/waiting at the garage. But it's easy to underestimate: it may well be 10 minutes-ish per wheel, but this ignores the time spent wrestling the 8 wheels from/to their storage space, plus the relative hassle of having to have somewhere to store them at home. I should have probably not interfered: she'd not really have missed the money, and I could have spent that hour+ doing something more fulfilling (maybe).