How often should you add grease to your trailer bearings? I always thought once a year? Does anybody have a good answer to this. Thanx.

do you have bearing buddies.  I do mine ones a year.

I have Bearing Buddies on mine. I pack the bearings every January 1st .

I pull the hubs, repack, and reseal twice a year. Been doing this for years and have never had a bearing failure. I do not use bearing buddies. Just the standard dust cover.

Biggest problem with the bearing buddies and bearing failure is that most put too much grease in them and ruin the inner seals. Several of my cohorts were having problems, and found that was what they were doing. Went with the standard dust covers and have had no problems since. They too reseal their bearings about once a year and have had no problems. I'm just comfortable with the twice a year check.

I do keep a complete hub assembly ready to go under the rear seat of my pickup but have never had to use it.

If you have the older style "sealed" hubs, usually once a year is sufficient.  Though you should check them often.  If water leaks in it can ruin the grease, causing friction and bearing faluire.  While your trailering just just feel your hubs for excessive heat.  they should just be warm not burning hot.  It they are too hot to touch you got bearing/lubrication issues.

If you have the bearing buddies like I do they have the blue diaphrams that extend out past the hub when they have enough grease.  When you can''t see the blue passed the hub its time to add grease.  You may have to take the black PVC cover off to see it if equiped.

I'd reccommend the waterproof marine grease.  More expensive upfront but a lot less than having a bearing go out on the highway.

Even if you have the bearing buddies you should inspect/replace the bearings once a year and re-pack if you want to be on the safe side.  

Forgot to mention;

Be careful not to overfill the bearing buddies as you could blow the rear seal out of the hub.

Forgot to mention;

Be careful not to overfill the bearing buddies as you could blow the rear seal out of the hub.

Exactly, and that is what causes most of the failures with those setups.

Operator error.