"Age is just a number" is a faulty premise
When combined with a lack of annual inspection, yes, a recipe for disaster.
Back in 2009 (the engine was 10 YO) , I had a fuel leak above the rear starboard engine mount. The rubber was well wetted with diesel fuel for I don't know how long. I was aware the of the damage this could cause so I replaced it and a) almost broke the bank,
b) almost broke my butt.
Never again would I go through that. I annually inspect the mounts for contamination every year when I go over the engine. My other big check is the alignment every few years when I check for deteriorating alignment, particularly vertical alignment and no indication of anyone dropping yet. Combine all that with no vibration in the cockpit, and I'm not changing my mounts at 25 YO unless something ugly rears its head down there.
There is also some magic number (which I cannot locate again) of something like 1/4" to 3/8" drop in the supports before considering a changeout.
Other than that, sorry but no experience with Ellebogen mounts other than their price is certainly attractive compared to the original Yanmars.
