Harman XXV-10yr maint./parts replacement?

Welcome to the forum ... you might have to have some patience while waiting for Harman owners to provide advice. Many members have shut down their stoves and moved on to warm weather activities.

You could try a search on the ESP from past conversations (box upper right). Not exactly sure what the life expectancy is for them. You can probably hold off on the igniter since a handful of pellets soaked in hand sanitizer can get your stove started. An idle spare waiting on a shelf isn't a bad idea either though. The vacuum switches tend to be fairly stable so just keep an eye on the hose to make sure it is not cracking or splitting.

I'm sure others will join in with recommendations...

Every pellet stove can benefit from a new combustion blower about every 8 years. I'd look into changing the burnpot gasket too

Go ahead and order some replacement parts to have on hand. They will not go bad sitting in storage like they do at the dealer or internet suppliers joints. Personally I do not fix something if it is not broken. That said if your ESP being worn is causing issues then maybe it is time for a replacement.

Some things can be done as preventative maintenance and peace of mind like mentioned above. Pellet stoves do not need oil changes every X,000 miles unless you count cleanings as those oil changes. So I will put it this way..... Do you replace a working water pump or fuel pump on your car or truck just because it has 90,000 miles on it?

Your call but what I would do personally and many here also do is stock yourself with known wear items and parts to have on hand when they do fail. Most repairs and replacements do not take tons of time and are fairly easy and simple to do if you are half way handy. Have you replaced your rope gaskets? Those are usually recommended also. I am not real familiar with the XXV's so I'd also research them and maintenance stuff or when it is a good time to do what for that particular model. Most Harmans are about the same with wear items and such too. There are some here running old Harman Invincibles that have hardly done many replacement parts.

Lastly, A stove that has been well care for over many years will likely out last newer ones that do not get their oil change regularly etc;