The type of knife might be a factor. I like flipper tabs and slick actions on ball-bearings. In theory, that could be more prone to issues from dirt, grit, etc. In reality, I've never had a serious issue.
Of course, my knives don't get very dirty. I'm usually in office-type environments. With the exception of opening a bag of something edible, I don't use my EDC knives for food prep. The toughest things they cut are usually cardboard and zip ties. I clean and strop the blades as needed. When I'm camping, hiking, doing a rougher project, etc.; I just carry a fixed blade.
Pocket lint is the main infiltrator for my folders, along with a little bit of dust from paper products or cardboard. I've never had it jam up the action and most of the accumulation seems to be down around the spacers and lock bar anyway. Every once in a while, I catch a little wisp of fabric or something in the action but that's easily removed. I've gotten a rust spot or two over the years but often in something that's been sitting in the bottom of a drawer or left in a humid place. In many cases, the internals of a budget folder are dirtiest for me when it is new out of the box.
The type of knife might be a factor? Yes, that is true. But moreover would be the use of whatever knife. So, as long as you don't carry finicky or garbage knives in an environment prone to issues, then you're good to go right? I mean, you said you carry fixed blades when you think it's needed. So why are tool free take downs intriguing?
I uh, have never concerned myself with paper dust.
It has been my experience, and this is just me, that one should try many different things in many different situations to form lasting impressions and make subsequent recommendations.
Dust from paper products? Like many here, I've had folders and multi-tools that have seen fish scales, guts, feathers, fur, water, sand, mud, dried grass, bark, canvas, linen, comm wire, and bunch of stuff I've forgotten. I choose knives based on performance.
Never have I taken a knife apart and I didn't even know that was thing until the internet.
I absolutely understand that designs have changed and again, I have zero issue with folks wanting to take their knives apart. But tool less design as the future? Nah. Just choose the right tools for the job.
