It depends both on how much I like it and whether its in that perfect stage of beat in. I have a champ teebird that now turns over just perfect, even on lighter throws that would kill me if I lost. It took a while (and a lot of trees) to get it to that point. Where if I lost my new teebird, I'd take about 10-15, but no more.
I've only been playing two years and find myself progressing to the point where I'm only going to buy the molds I like best and have multiple copies of each. New ones fly like new ones, so if I lost it, I wouldn't feel so bad. It's the old ones in that sweet spot that mean the most. I'd freak if I lost my roller disc, too.