complete over-hauls.. rarely if ever.. New stock when I lose fish, or they get new tanks. I'm happy with my gar tank and my Bichir tank stock lists. I'm upgradeing my planted tank soon.. but most the old substrate and plants will simply be moved over as well as stock. I'll upgrade equipment as I can/it's needed. But the only time I ever do a "complete" set-up is when I'm adding a new tank to the collection 
