SIPping is best, especially, when markets are up. Generally it’s good across the market cycles.
One can do lumpsum investing on the upside but the returns would be lower because of time & price corrections.
SIPping, even if done on upside, will provide better returns in case of time & price corrections.
I’ve a simple rule:
I invest Lumpsum amounts when stocks are down. Because stocks don’t stay down for long periods of time.
I do SIP almost all the time & even when markets are up. This covers the downside risks because I’ll get more units in case markets are down.
In nutshell, I invest lumpsum when markets are down. Like in 2020 & 2022 down markets.
I do SIPs almost all the time. Doing it since past 8 years.