Consider this: Petrol in most states of India costs over Rs 50/Lt Whereas Auto LPG costs less than half that price(around Rs 23/lt). Auto Lpg gives around 80 to 85% of the mileage of petrol even so, effective savings is around 30%. So if you are located in a area where Auto Lpg is available as an option and your average travel per day is 10 Km or more then - Go for it.
On a full tank of LPG(45 lt tank), I can take 5 people approx 780 km before it runs out of gas.
Somethings that you should consider are:
a) The price of the kit – Rs 22, 000 to 24, 000 in Mumbai.
b) There are relatively fewer LPG filling stations than(say) CNG.
c) Conversion to LPG requires the installation of a large tank in the dicky.
d) Auto LPG being a clean fuel, the engine life of your vehicle is increased.
e) With a tank full of petrol and a tank full of LPG, you can probably go over 1200 Km non-stop
Inspite of there being fewer LPG filling stations, it is still worth going for LPG as savings are very real and big. Personally, if the LPG level in my car is less than half, then anytime I go past a LPG filling station, I fill up the tank. That way I don’t have to make a special trip to the fueling station. There is already lot of information available of the net covering these issues. A good site is https://cng-lpg-conversion.com