RO water purifier buying guide

Go for UF+UV. Most of the people doesn't need RO water purifier.

If water is overly hard with high tds and harmful heavy metals then you can consider RO.

first is to check for TDS and if your source water say borewell has TDS above 500 then go for RO, current RO devices in the market are able to handle TDS upto 2000 and generally TDS below 150 is good for drinking water and for cooking but as time goes on your source (borewell) will definitely add more TDS as groundwater level is obviously expected to go down every year so point is now it (borewell) might show TDS as 400-450 but after 2-3yrs it can go to 600-650 (based on my experience)... 

if your current TDS is around 400-500 then RO will bring it around 40-80... was using Kent for 5+yrs and moved to Mi Water purifier in 2019 mainly for the service part as it (for my unit) didn't require any service at all so far and have been replacing the filters by myself (DIY and its the easiest among all current RO) every 1yr and cost is around 4k for all 3 filters but now they (Xiaomi) have stopped selling the device and getting the filters was a pain, my current filter life is for another 7-8months so need to see what is available in the market by year end, thinking of going LivPure method i.e. pay per consumption and they take care of the device and service (yet to deep dive into those details)

Not much info on Copper and water saving though as my requirement was to see which RO has TDS monitoring, filter life etc (mobile app) and filters can be changed by customer itself rather than calling service center and Mi was the best fit that time (and even now)..

Oh so no RO but only UV and UF, where can I read more about it? and also any recommendations for those devices? 

So RO is not needed if TDS is in control?

Any suggested models with RO UV UF and how important is Mineral/Taste/Copper? 

Also do additional features like direct hot and cold not complicate the machine and increase service issues? 

also seeing lot of cheap options, are they worth a shot?