How important is it to replace these?

I did the timing belt, tensioner and water pump 20,000km ago and am now replacing the water pump again, but will skip the timing belt and tensioner since they are close enough to new.

Is there any way to check the pulleys?
Or is this an "if in doubt, replace it" item?
I ask because I can't be certain of the age, however I've heard these pulleys can go for 300,000+km. I think it's safe to say they have less than 100,000km on them, but will they hold up for another 60,000km? (when I plan to get in there again)

I should add that I do not have balance shafts.

Rob, why are you replacing the water pump again!? I'm doing this one right now! What make? Did it fail/leak?

As far as the idler pulleys go ... if they feel good (bearings), then you can clean and re-grease them. I'll be doing this, as the pulleys still seem good.

The damper in the tensioner is shot, so I'll convert it to manual operation.

Martin,

Somehow the bearing in my water pump let go and the pump started leaking through the safety vents.
I attribute this to either a faulty pump, or improper belt tension (PS/ALT). There is a slight chance that the old pump was used after rebuilding the motor as it was not in my hands.
It was an OEM pump (from Chrysler) with "AISIN" embossed on the neck. I am replacing with a fresh reman from unknown source.

My pulleys spin freely and they don't seem to play at all. I will double check that.
What's the proper way to regrease these? Just remove the pully and spray into them? (assuming the spray grease is used)
What's the best kind of grease to use?

I've read that it is not advisable to use a manual (fixed position) tensioner on a daily driven car. They are OK on a dedicated track car as the motor (including timing) would serviced frequently and so the belt tension is closely monitored.

Thanks for the comments. Anyone else?

Hey Rob, how badly did your wp leak? Mine seems to be leaking also but it is not in large ammounts, it doesnt seem to pour out just come out in droplets.

When I noticed it was leaking, it was about a drop every couple of seconds starting as soon as the cooling system pressurizes.

After maybe 2 hours worth of driving like this, it was pissing to the tune of at least 5 drops a second (regardless of pressure).

Release the tension on the PS and ALT belts, then shake the water pump pulley with your hand. If there is play your bearing is shot. If there is no play, maybe it's just the gasket that is leaking.

VERY carefully pull the seal out of the idler pulleys with a small hook. Clean it out with a degreaser, and pack it about 2/3 full of a good wheel bearing grease, or preferably a synthetic grease. Pop the seals back in and your done.

What Nick said.

You can use a needle, xacto blade, dental pick, jewlers screwdriver to pry the seal(s) off. Try to grab them from the outside edge to prevent damage to the inner seal.

For cleaning you could use spray them down or soak in a glass jar with brake/parts cleaner. Camping/Naptha/Kerosene works great too. When they're clean & dry (air gun?), give them a few drops of motor oil and give them a light spin (never spin when dry or with only cleaner in them!). It's easier to hear/feel how damaged they are with just light oil. New bearings would be almost silent.

Industry says 1/3 of the inside volume should be packed with grease. Too much will cause overheating. Trusty Mobil 1 Synth grease (Can Tire?) will work great, but any good bearing grease will do. Don't use chassis or moly grease.