If it is running a bit sluggish then could be the MAF is on the way out. Only replace with the correct genuine Bosch part.
As long as they are regularly serviced as per the schedule and using quality oil and filters they shouldn't sludge up. My engine has done just over 375k miles & never seen a Terraclean yet. Still runs fine.
Do give it a good thrash through the revs every now and again once the engine is up to temperature - it blows the soot out.