Buying RO water purifier spares online. Reliable sites and brands suggestions needed.

rimgeaper

Beginner
I'm planning to assemble a tankless RO purifier for home use. I found the following sites selling RO spares

hitechro
pearlwater.in
jeitechaqua.in
satyaneer.com

Are they reliable, have any of you ordered from them?

Also Konvio Neer parts seem very popular on Amazon. Any experiences with them?
 
Piggybacking on this thread, when is it the right time to change the RO filters? I have not changed mine in almost 1.5 years and I checked the TDS the other day and it was 22, whereas the raw water was 350. Does it make sense to change the filters right now? Or should I just change the prefilter? If not, what is a good time-range and metric?