I went to a furry convention and spent the whole con wearing the birks with thick socks underneath.
I looked goofy as hell, but by the end of the con they were all worn in.
One thing that can help as well is rubbing a little oil into the leather wherever it makes hot spots on your feel to soften the leather a touch.
Myself and several of !y coworkers use Linux at work bit, to be fair, it is a tech job.