It’s the same for all filters…Glowforge has never hidden it.
But…I do agree that that can definitely be easy to miss. It’s not something that new users are expected to know if they’ve never used a filter. Unfortunately, there’s no other way for people to find out about it if they don’t read about it on the forum, or do outside research of their own. It’s just physics. The small pores from a filter designed to screen out smells can get clogged, and when they do, they stop working. Some materials are worse than others, and MDF happens to be one of the worst. It’s full of glue holding the paper pulp together. Melt that with a laser and it gets sticky. (There are others, including some hardwoods and softwoods that are just as bad in my mind, but Glowforge will only talk about their proofgrade materials here.)
Things to avoid are anything with a lot of resin in it (padauk, pine, cedar, some oak) because it’s going to throw up sticky smoke, that will narrow the size of the pores, and then particles are going to further clog them. Excellent candidates are stone, paper, metals, dry hardwoods, acrylic and leather. You can try out a prefilter to catch some of the excess particles, but those will need to be changed more frequently.
I’d just dodge the draftboard with the next one and it will last a lot longer for you. Short of that though, there isn’t really a good way to say how long exactly a filter will last…it just depends too much on what is being burned in the machine.
(Sorry, I just don’t know that anyone has those answers.)
The most economical answer by far is to vent outside if there is any way to swing it. I have mine set up with a quick connect so I can switch to venting outside when cutting draftboard, and save the filter for the stinky stuff like leather and acrylic.