I do enterprise sales software, the longest I’ve been at a company is four years. By definition I don’t get burned out.

I have a ramp up Year where I make okay money, two years where I destroy the number and make a ton of cash, then the company has either gotten acquired, or they split my territory so much I had to leave.

I don’t know what I would do if I stayed at the same place for many years, but my experience is that companies get tired of cutting huge commission checks for the same guy year after year. This was the pattern at Oracle, then Siebel, then Salesforce. Eventually they just hire so many new sales people it is impossible to make 300% of quota, they will start to take away your accounts until they have a bunch of people making between 75% and 150% of quota.

I keep moving to early stage start ups, where there are only a handful of guys and less territory friction. Plus when your company gets acquired you usually get a nice chunk of change in terms of stock options too.
However, two of my last five jobs were situations where the company wasn’t as described with no product or bad leadership, so I left quickly and that is always a risk too.