There is no limit to the amount you can invest in a SIP. The minimum amount that you can invest is Rs. 500 per month.
There is no maximum tenure of a SIP. You can invest as long as you can. The minimum tenure you can go for is 3 years
Yes, you can anytime check your returns with SIP investment calculator and increase or decrease the SIP amount
Different types of SIPs are available in the market like: