When is it ok to buy a depreciating asset?

[David J.]

HI,
I have been a real estate investor for many years now. I have been very disciplined with my investing strategies, making sure to budget, and invest as much as I can. 

I now have about ~ $4M RE portfolio, ~$240K in stocks, and decent monthly cash flow.  I am about 70% leveraged or less.

For years I have been driving an old beat up pontiac that now has 250K miles on it. (still runs great)

I am now in my 40's and for some reason getting an itch to buy a nice car that I totally do NOT need. Even though it's 5+ years old It most certainly would continue to depreciate and goes against any advice I would give to someone else. I don't know how to ditch the urge. It seems to be growing stronger with each passing day.

When is it ok to buy something stupid?