The problem with today’s SIP is the marketing around that and the mutual fund industry is guilty of that. A SIP is just a method of investing and it is not a guaranteed road to riches. Now, having said that, it is still the best tool available to a retail investor. Now, is a SIP perfect? Hell now! But for salaried people, and most Indians are, it is the best way to invest given that people won’t have huge amounts of cash lying around.
Now, should you create a SIP and forget? Absolutely not! Plenty of things can go wrong. You might pick a shitty fund, or the next 10 years maybe a prolonged bear market where equities do nothing. This where you asset allocation comes into play. For example, in the last 1-year, a Liquid fund would have given you more returns than smal-cap, mid-cap, or a large-cap fund
Japan had a bear market for 25 years
A SIP wouldn’t have saved you in this case.
Here’s a nicely written article
When you get in and out and you luck are equally important. Unless you know how to time the market successfully, SIP is the best way of investing but it isn’t infallible.