Helmets are disposable. I get whatever's on sale, use it until it gets nasty, then replace it with whatever's cheap. Every time I order anything from a place like Nashbar, I take a look at what saddles are on sale; if there's anything decent, I'll put one in my shopping cart.
Helmets do wash.
I am in alliance with rum as they are a disposable item.
Buy what fits, buy light in color, a bit cooler.
I avoid long pintails and "horns" (I don't want my head to spike and the body not)
Buy with the intention that you will retire it in two years anyway.
Expanded Polystyrene which most affordable helmets use does not age really well.
for me, Bell helmets fit well. Giros don't as an example. ( funny as Bell is now owned by them)
I found the Bell Solar, meets the above criteria for me, at least last year.
Next year? Nobody leaves well enough alone… Grumble.