I used to tip around 10 in Bangalore. But I would skip sometime if there is a queue and it would be months before I could get it filled again (out of my lazyness). I later bought tyre inflator. I check the pressure weekly/fortnightly (generally on Sundays). That has worked better for me and I save time at fuel pump.
In case you want to buy the pump I bought, you can get it from https://www.amazon.in/Michelin-Digital-Single-Barrel-Foot/dp/B07CQ7B1P3