I have a Jet 1x42 belt sander that I use in my garage quite a bit.
Mostly for sharpening or shaping metal but sometimes wood.
I bought 2-3 years a bulk pack of I believe Deer brand alum oxide in different grits.
No complaint about the wear or the grit but seems lately that they break where they are fastened very quickly.
Mostly with metal shaping but not exclusively.
They break way before the grit is worn down.
I am getting tired (also running out of belts) of replacing them.
Is it just the age (est 2-3yrs) or the brand, or something else such as use?
I wouldn't mind getting or trying some zirconia or ceramic but not if they are going to break too as they are substantially more expensive.
Any advice?

Thanks

I'm sure you're aware of it, but just to make sure... are you sure you're putting the belts on in the correct direction? There's arrows on the bottom showing which way they should go according to the direction they're turning. The overlap of the joint can snag and break if they're backwards.

Yeah, I know about the direction.

Since they are local I get my sanding supplies from Supergrit.com

I have been very pleased with their quality and selection. You might give them a try.

Having said that, yes, belts do age and glue joints become weak. I have a selection of grits from broken belts that I use when I need a small piece of something.

As for getting the belt on in the right direction - some belts are spliced with a simple overlap. These are the ones that need to go on correctly, so the direction doesn’t cause the splice to peel apart.

Some belts have an additional piece to join the ends. Looks kind of like reinforced strapping tape. These are actually “bi-directional” and they can run either way.

I have repaired a splice that is about to break with two small wood blocks, a clamp and some super glue. The blocks give even pressure under the clamp and may get glued to the belt. Destroying the blocks is no great loss. Rather not glue the clamp to the belt.

Finally, heat can be hard on a glued belt splice. I try to stay aware of this while sanding. I have a Delta 1”x42” sander that gets a lot of use. Much like yours. It might be older than I am but I keep it running. A very useful tool to have.

Is one of the rollers unpowered? If so, is it turning with no friction or catching when under tension?

Are the stored belts or belt sander exposed to direct sunlight? UV damage?

I had an issue with plastic line breaking in my gas string trimmer. Turns out it was from the trimmer line package being stored in front of a window in the garage.

 
I get my 1x42's from McMaster Carr, from the finest grit (like 440 or something, rarely used) up to 3x grit heavy duty. I get the blue belts (and discs) for general and heavy duty, but I forget what the abrasive is made of. Never had any breakage problem, and I use them almost exclusively on metal. I keep a 3x grit (32 or 36, I forget) on the disc, and usually 80 grit on the 1x42, and get a good long life from both.
 

I'm thinking the belts are just aging now and the glue is releasing.
Nothing out of the ordinary in fact they are breaking (separating) very easily now.
Think I will just buy some more and try them.
Any places you guys like to buy abrasives from?

Aging will cause them to break quickly. Sometimes as soon as they are run the first time.

It's the age of the belts, the glue joint deteriorates over time and let go very quickly with age. Fresh belts seldom do that, however changing brands may help as well. Norton is a great company with high quality belts.