Hi, is your air purifier still working now, since the filter "expired" one month already?

I'm considering getting one for my bedroom, not sure 3C or 3H.
Thinking of adding a layer of fine mesh (macam computer casing fan intake mesh) to prolong the life of the hepa filter, but if it has usage-based expiry then the benefit isn't much as I'll still need to replace the filter.

Thank you for the confirmation.