Opinions on treating parasites?

Would you treat your herps if they have had completely normal stools (solid, no mucous, no foul smell), normal behavior, normal weight gain, and normal appetite for months, yet still have parasites turn up in their fecal tests?

The list continues to grow... up to this point, I have dealt with pinworms, hookworms, coccidia, giardia, flagellates, clostridial bacteria, and spirocysts (I think that's what the receptionist was trying to say) identified in my gecko's stools. However, for most of my geckos, none of these parasites are obvious. You would think coccidia and giardia would present the most problems, but the geckos that had them have never once had a runny stool (only one presented serious malnutrition, but that's because he also had hookworms).

I'm stressing out now, because some of these parasites were discovered upon fecal smears, but I've only had smears (in addition to floats) done on roughly half of my animals. I still worry that inconsistency of not having both flotations and smears performed could mean inaccurate results, which makes me want to just shotgun all my animals with Flagyl and Panacur just to be safe.

Or am I just worrying too much? I can't be the only person dealing with parasites. I only find out about this stuff because every animal that comes into my (modest) collection gets tested. I wash my hands before and after handling any animal. I remove poop and provide fresh water daily. Is that why they don't show any symptoms?

I guess my main concern is.. Is it actually helping my animals to give them medicine? Given how easy it is for reptiles to contract parasites through feeder insects, veggies the feeders eat, water that they drink, should I constantly be worrying about parasites? Should I constantly be monitoring their stools, or should I shotgun them all with treatment?

I am switching to a new vet, by the way. The previous one was too expensive for not being much help.