How often do you replace this?  I haven't used mine so the tread is still in perfect shape, but is tire rot a concern over time even if I store it in the garage?  It's not exposed to the sun or the elements other than when I'm using the boat.

Many tires rot from the inside out over time. You can't visually see the damage. I believe they say 7 years is the safe zone. I am no expert and I am sure others will chime in.

Anything over 7 years old cannot be deemed safe. 

I'm a bit OCD on trailer safety, but replace my trailer tires (including the spare) at 5 years regardless if tread wear is light. The cost of the additional spare tire isn't that much more and is good insurance if/when you do have a flat. 

I replaced the tires on the trailer 3 years ago this past April.  The spare is 2 years older though.  So it is 5 years and 1 month old now.

 

I think I will look into replacing it this season.  There appears to be nothing wrong with it but a spare tire failure due to lack of replacing it seems foolish to me.

I replace all trailer, vehicle tires at the 5 year mark including spare.

My spare for boat trailer lays on the back of truck for months at a time but keep it protected with 303 and the stuff does work.

A buddy of mine had a flat when we were trailering his boat to Canada years ago. He had a relatively new spare but it was down to about 12 lb PSI when we put it on. It blew 15 miles later as we got into town so we were okay (barely).
 

Nowadays I make sure to check the tire pressure on the spare whenever I check the other tires… plus I have a tire compressor in the vehicle now. 
 

I seem to get smarter every time something goes wrong .. lol

2 hours ago, FryDog62 said:

Nowadays I make sure to check the tire pressure on the spare whenever I check the other tires… plus I have a tire compressor in the vehicle now. 
I seem to get smarter every time something goes wrong .. lol

All of this make perfect sense to me  and perhaps any anyone else who works on eliminating risk

and not just trying to manage it.

btw - consider carrying a few spare trailer wheel lug nuts with you on the road.

Don't ask me why 

A-Jay

1 hour ago, FryDog62 said:

A buddy of mine had a flat when we were trailering his boat to Canada years ago. He had a relatively new spare but it was down to about 12 lb PSI when we put it on. It blew 15 miles later as we got into town so we were okay (barely).
 

Nowadays I make sure to check the tire pressure on the spare whenever I check the other tires… plus I have a tire compressor in the vehicle now. 
 

I seem to get smarter every time something goes wrong .. lol

I was going to mention this as well. I checked my spare in my car one time before a road trip and it was supposed to be at 60 psi but was less than half that.

Just replaced all three of my trailer tires 3 months ago(I have a single axle trailer). Got a great 3 tire deal from amazon.

Depends on how broke and how hillbilly you are…….. yall probably know my stance 😂 

 

my current spare is a nearly brand new tire I wore wrong by limping along a leaky tire if that tells you anything……..

 

Granted I have only used a spare to get to the tire store, and the only time I’ve ran into trouble was on Memorial Day when everything was closed 

Most trailer tires age out before they wear out. I don’t hardly use my trailer, I cover them after soaking them with 303 from time to time. They still check out, and crack.