"ls02" wrote in message
I am building an addition to my house and thought of upgrading my 150
...

In general, if you are not tripping your main breaker, then you don't
need more capacity, but...

If you need to replace the main panel, then I would suggest upgrading
to 200 amps. The reason being that electric vehicles are on the way.
These can draw upwards of 70 amps while recharging.

If you don't need to replace the main panel for the room addition,
then no reason to upgrade now. You could always do that later if
necessary.

Also another way to look at it. Inflation. Cheaper to do things now
than 10 years from now... But also factor in interest if you need to
borrow money to do this. Might be less expensive to do it later at a
higher cost when you can pay cash.