Do you know the difference in cysts and ovum of parasites to be able to determine if it is round worm, tape worm, hookworm, flukes and the like or do you know the difference between hexamita and giardia? Improper diagnosis can lead to improper treatment which can lead to complications. It's nice to be able to learn how to do a float but you also need to know what preparation (as in stain, fluid, etc) for what parasite to make the proper determination.

For 99% of reptile owners just take it to a vet and let them do it, they are trained to know what to look for and what to treat with. I spent 8 years working in an infectious disease lab and even I have a hard time differentiating ovum and cysts. The last thing you want to do is misdiagnose say cryptosporidium for undigested animal matter.

I could do my own fecals but would still need a prescription for anti parasitic meds and would still need a positive and proper ID to know which med to treat with (you can't use a broad spectrum on every parasite and some need to be treated in order) so why should I waste my time when a fecal is less than $20?

In short, unless you are someone who has hundreds or thousands of reptiles and can afford the cost of material and high power enough scopes that have proper lenses (you need polarized lenses for some IDs) then don't waste your time, you are not a microbiologist and it isn't that easy, trust me.