>>1513387>>1512216These guys know what's up.
Made the mistake of buying my first pair of hiking shoes and boots too small. Fucking pain and regret going downhill with toes hitting the front. Replaced both of them a year later.
Best tip I got was in a hiking shop in Berlin from a veteran hiker lady when trying to decide between 2 different boots: "Fitting good is not enough, they have to fit perfectly." So try multiple brands as they have very different fits. Don't just go straight for a brand that some /out/ guy recommends.