I too could NEVER do rescue on my own.

The ogranization I volunteer with does ALL the vetting and that includes: FeLV/FIV test, distemper and rabies at the appropriate ages, worming, flea treatment and neutering at the appropriate age. PLUS many special needs cats that have had other, extensive medical care.

As for who is a good pet owner. you screen the people, ask questions, visit them, check their vet reference, use your instincts and them hope for the best.