The rate limiting factor for me is definitely TIME.
Fortunately, I can afford the mods that I like but since I am a hands on kind of guy, and took my AV on as a hobby, I was determined to do as much as I can myself.
During this process, I actually amazed myself because I learned and picked up new skills I never had before.
My dad always helps me--he has no choice I guess because I built him a brand new house to retire on and he lives 1/2 mile away from me. I don't own any tools but the workshop in his huge garage looks like Bob Vila's workshop.
As far as time of the day when I do mods, my favorite time is after 9:00 pm, all alone in my garage, wife and kids are asleep, soft music in background, phone off the hook, and i am in modding heaven!