Yup I'm still flabbergasted when people don't filter their solutions. So I always ask and try to make light of it, because I really am curious. And a lot of the new people don't know about it, so they have never even thought of it as an option to consider or ignore.
Personally, I don't see it being difficult but I have worked in a lab before. I don't use pens either, but those that do normally have pretty good experience with the whole process so it is a simple add on to just do it during that process. And I don't completely agree with the AI answer, they aren't accurate in some way or are throwing a guess in there most of the time, it is crazy. My own thought process has always been that we have zero control over the production, quality or the cleanliness of the labs, or shipping. It's the grey market and we just accept that. I do have control over the filtering and sterilization. I understand the sterilization process and the materials they are made of. Even if it filters out bacteria, bits that didn't dissolve, or debris one time it is worth it to me. It's just my personal preference to do it every time and I'm curious why others don't. I have heard the cost is too high. Or they just can't keep the area clean. Or I see others worried that it could cause the issue. And even further, many don't know what it is.