I'm growing Perpetual chard for the first time this year. So far, I'm impressed. It's milder on the beetiness (I swear that's a word) than the rainbow type, and I actually appreciate it not turning my recipes pink. It's supposed to be resistant to bolting, but I haven't had it in long enough to say for sure if that's true.
I think that might be the same as I have, though Spinach wasn't on the seed pack...
I just harvest some of the leaves. If the outer ones have gotten a bit raggedy and bug-eaten, I leave them and take some medium-sized ones instead. I harvest pretty severely - 50% or so of the leaves at a time - but the plants always bounce back just fine. I kept some chards alive for about 8 months last year, harvesting them each about once a month.
Name: Carol Noel Hawaii (near Hilo) It's all about choices.
More or less what I do too!!! My grandmother used to say, "eat them all, the holes in the leaves don't give it a different taste"... but I don't like the idea of eating something a bug may have left it's spit on!!!!!