Trying to buy at the “perfect” moment is the fastest way to drive yourself mad and, often, to do worse than if you’d just kept it simple. Even professionals can’t reliably time this market. So don’t set yourself a game you’re statistically likely to lose.
The unglamorous alternative that actually works for most people is buying a small fixed amount on a regular schedule — the same £30 or £50 every week or payday, no matter what the price is doing. Some buys land cheap, some land dear, and it averages out without you having to predict anything.
It’s boring. That’s the point. Boring is what survives the wild swings. I wrote more about the maths and mindset over here.