You'll want to fix most of the problems relatively late in development, although I can't recommend enough testing on the most low-powered hardware from the get-

You'll want to fix most of the problems relatively late in development, although I can't recommend enough testing on the most low-powered hardware from the get-go. It will let you know immediately when you've written slow code. It's easier to fix a design mistake just when you've made it than when you've got six months of development hinging on the poor design choice.