Perhaps for relative newbies like me someone could advise of a good
method they've devised for upgrades - every 6 months is quite
frequent! For bookmarks with winblows i used a portable version of
firefox allowing me to use my precious bookmarks on different
machines. I was a teacher and so had a lot of bookmarks for research
purposes, another i'm a hobby historian, and also a classic car
enthusiast, and also a considerable number of bookmarks on the IT
side.

With linux i've found the best method is to use Foxmarks... another
with google didn't seem to work so well.