Timing the markets is nearly impossible. Even if you’re lucky enough to catch the best days, your returns aren’t drastically better than someone who invests regularly or even at the worst possible times.
Haven’t done testing myself yet for investing, and yes just buy and hold is fine if you can manage fear and greed and don’t vomit when things get tough - but as an opposite view, i remembered this podcast.
Don’t ask me anything, saw this few years back. For most people who cannot track and are emotional, probably best to not bother. But Mutual fund guys do have an incentive to spread studies like above cause they make money off commission.