Boot Insole Width Governed by Feet or Boot?

Bit of a random question - but are boot insoles made such that their width matches your feet or boot?

I ask this because I would like to get some insoles. I suspect that next time I get boots, I will get narrower boots. So - I wondered if I got insoles made now, whether they would fit narrower boots in the future.

Custom Insoles can easily be shaped by a bootfitter, using a variety of tools. Can't see a problem for you, but if they needed to be wider, you'd need a new pair!

shouldn't be a problem to make them narrower, as Bandit suggested, you may need a new pair if they need to be made wider, the insert is firstly made to your foot shape, then excess material id removed to fit it to the boot liner/shell