Typical lifespan for a 5 channel power amp?

Honestly, that amp will likely outlast you. The only parts that have a shelf life are the caps, and they will typically last 30 years or more (the dielectric can dry out). I stress "or more" because that 30 year figure is just an estimate. Cool running, overbuilt amps like the Titan will likely last much longer then 30 years before there is any noticeable degradation in sound quality. Enjoy it! The caps can also be replaced at a fraction of the cost of a new amp. My W3 is around 20 y/o and still going strong. Dead quiet, no hums whatsoever, and used daily. Congrats on the deal, that is a heck of a HT amp. I also use Dynaudio speakers.

I’ve had my RMB1095 since 2005. always loved it for HT, not so much for 2 channel music....it's still going great

I actually reached out to Simaudio and they replied right away. They said since this unit came out in 2001, every single one of them is still "active". They only see about 1 a year for servicing (and he said it's usually because someone shorted a binding post or defective startup). He recommended if I have an opportunity to be without the amp for a few weeks I send it to them for cleaning and calibration...WHAT??? I can't go without this thing for 1 day, LOL!!!

@perkadinI  Thank you for the kind words and info...What Danes do you have? 20+ years ago when I started out in this hobby I went through all the usual's (DefTech/Paradigm/PSB/B&W) and someone recommended Dynaudio. Literally the minute I listened to the Audience 82's it was game over. I remember thinking I didn't even know speakers/sound could get this good. I still miss my Audience speaks, but the Evokes have filled that hole more than adequately :)...

 @jl35 I honestly LOVED the 1095 more for music than HT actually, lol...There was something just pure magical about the Dynaudio/Rotel combo for me back then. I loved that amp!

I have the Contour 1.8's, 1.1's and center. Like the Sim gear, Dynaudio overbuilds their speakers and are built to last.  At one point I had them set up in a HT configuration but now they are in two separate rooms after moving. So I have a 3ch HT setup and use the 1.1's with a tube amp in the bedroom.  It's nice having a secondary system, and I was pleasantly surprised how well the 1.1's work with tubes in triode. I think their relatively flat impedance curve really helps.  People make a huge fuss over sensitivity and tubes but there much more to it then spl levels.  

20 years or more for a solid state amp is not unreasonable.

The biggest issue I can think of for multi-channel amps is ventilation.  Shoving 3 additional channels in the width of a traditional 2 channel amp is a challenge for space and air flow. If they are put in a tight rack with little air flow they probably won’t do as well as an open shelf.