Apologies if this has been done before, but I’m curious what works best for you based on preferences and context. Personally, my tastes are kind of all over the place, but I carry generally from the 3.5” to 5.5” neighborhood. No particular reason. Though by no means would I feel underknifed with a 3.0” or slightly less for everyday tasks. I’ve found smaller knives to be more convenient for opening packages.