Here are two pictures made by a fellow Volvo driver who's recently taken the time to open his fuel filter too.
This one came from a 940 with an odometer showing 780,000 km (~485,000 mi), it's uncertain when the last time was when it was changed. No make could be discerned anymore on the rusty filter.





I wouldn't like to drive around with this, look at all the gunk in the inward facing folds.

Edit: now that I found out how to include photos in this forum, a look at what I found in mine again (notice the different construction).
Peculiar to see how mine's solied with grey/anthracite particles while his are mostly brown. Would exceeding the replacement interval extremely be the reason the filter turned brown?





And that was dirt in the fuel coming from this rather clean looking tank: