I don’t know if the ‘Show my windows and tabs from last time option’ wouldn’t do the same as what you are trying to achieve, I don’t have any sessionstore-xxx.js files on my system, only one nsSessionStore.js file and that was last modified in February 24. I also like the History, Recently closed Tabs functionality, these two options for me meets my needs and no overhead of lots of .js files being created and accessed. As Tech mentions there is a risk in excluding files, using wildcards can increase that risk, though with a full path in this case I feel that risk is limited.

Your system should be more than up to the task, but if you have lots of other applications running then there will be a bit of sharing resources going on.

Welcome to the forums.