I think that both Fuzzy's and George's reply sum up the problem. You need to know your local market, to determine whether or not wormy bowls will sell. I can sell the odd one, now and again, but certainly not too many of them. These days, if I turn a lump that turns out to be too wormy and I haven't got one in the shop, then I'll keep it, but if I've already got one for sale, I don't bother finishing the next one and it usually goes on the fire.
Les