10 years or until I get bored and want to try something new.

DK

PS Friend had a 6 year old lil Tex.  He says it died (without much of any troubleshooting).   Went out and bought a new Texas knockoff.  Gave the Tex away on Craigslist.  Most likely a new Ortech controller and someone has a less than $100 investment in a pit that will last for years to come. 

These are some great replies.  I, unfortunately, have a disposable mentality.  I dont want a 10 year old computer, car, cellphone, etc.  And i would like an excuse to upgrade from my GMG JB amd RecTec 680.

But I suppose my two pits will last many, many years.  For the price paid and hours of service even a $5000.00 pit is a worth investment

 My Traeger Li'l Tex was 5 years old when the end of the auger tube eroded past the fire pot. Traeger won't sell the assembly for some reason. Luckily I was to acquire a like new replacement..Rust: chimney cap edges, lid and a few small spot in the body...Installed a stainless steel kit to compensate.. Ground and painted the few small rust pits. Kept it clean and polished .  Two hot rods and one fire pot were replaced. Controller readout wouldn't fully display when cold ,at times.. Stored under cover, covered..Never covered if wet.. Yearly pellet consumption 400 lbs ish. Cooking temps mostly, smoke and 325º.

Now I have a Memphis Pro..It was hard for me to convince myself to spend all that $$$. With free shipping and discount for the non wifi model, I was convinced. I didn't wan't wifi anyway.
The only problem I expect to have is the igniter at some point..Now I go thru almost 80 lbs of pellets per month..Extrapolate to 800 lbs/yr. I slow down in winter..
Not only do I expect the Pro to outlive me. I find it so easy to maintain. It's 1/10th the work of the Traeger. No bucket or grease trough. It heats up quickly, maintains heat and can get far hotter.Direct flame cooking to boot... The long and short is, in the end it should end up costing less and consuming fewer pellets due to its efficiency.

I would assume as long as im taking care of it the structural parts of my grill will last 20+ years. I do figure there will be  component repair or replacement along the way but no different the long term ownership of my other toys.

I'm in the Memphis camp, had my Pro for 5 years, just replaced the igniter, first and only issue.  If I wanted to spend the time and effort I could make it look almost brand new. Seems with the rare and occasional fix this thing will outlast me easy (I'm 57)