[asveikau]

How much maintenance do those fans require to keep working well? I feel like the common thing is to basically not touch them, and they get pretty gross and don't seem to do much.

Edit: I got downvoted for this? I feel like I've seen a lifetime of these fans being decades old and in poor shape. I think you folks are vastly overestimating how many people clean those or replace the filter.

[tpxl]

They're basically char filters, so if you wipe them and change the filters every 6 months or so you're good.

I'd be surprised if the average change time is any less than 5 years though.

[osigurdson]

Very little maintenance is required but not zero. If it gets gross, wash it.

[cdtwigg]

You need to clean the filters regularly so they don’t become a fire hazard due to oil buildup; the better ones should have some kind of reminder system and will have filters that are dishwasher safe.