I subscribe to this methodology. When I find something I need, something that works better, etc I typically slowly buy enough of those items for all my kits. I keep a list in my little blackbook (really, it is little and black <img src="/images/graemlins/laugh.gif" alt="" />) of what I need for each kit, and cross it off as I get it. Some of my replaced gear gets cycled into kits where it still fulfills my needs or I give it to other members of my team who cannot afford new cool toys (unless the item is junk, than it gets round filed).

The best kits are built one piece at a time!