what kind of socks do you wear?

If you are developing blisters, the probable cause
is rubbing--indicating less than a good fit. Wearing a
good pair (or two) of thick, white cotton socks can
prevent friction between your feet and the insides
of the boot. There must be space between the boot
and your foot--thus permitting friction and rubbing.
---
Typically, the only off-the-shelf inserts are "Dr. Scholl's."
They come as either just flat foam rubber insoles,
or as orthotics with an arch support. Beware of the
arch support type, though. Different people have
different arches, and one size does not fit all.
---
Custom-made orthotics (with arch supports) are
made by podiatrists. They will make a plaster cast
of your feet, and have a laboratory custom-make
some orthotics that are peculiar to your feet. They
should provide the support and end the rubbing
and friction.
---
But of course, BFers usually try to avoid podiatrists!
---
In my work as a bus driver, I have to "be in uniform"
while on the job, and that means black shoes--
"service shoes" as I call them. They are a necessary
evil in order for me to make a living! :-) But the first
thing when I get off work when I hop into my own
car to go home is to take off my shoes and socks
immediately! I drive home BF, and stay that way at
home. "There's no place like home!", as they say. :-)