I can POSSIBLY understand losing baits if you are beating the bank. However, I'm not above swimming to get a lure that I've spent a good chunk of change on. If you are in a boat, there is almost no excuse to lose a lure unless you set the hook on something and snap off.
I'm with Hooligan. A good plug knocker (I carry two) will pay for itself the first time you hang an expensive bait. They are simple to use and a MUST for fishing any kind of diving bait, treble bait, bottom contact bait, etc.