Hi there guys, I just bought an 2006 Forester, automatic transmission, with 154k miles in it. A friend of mine who is a mechanic has recommended that I take it to a professional shop and have the transmission oil changed. I called one such place and the guy there flat out told me not to do it, therefore losing my business but strangely gaining my trust... Any thoughts?

I would say don't flush, but start doing some drain-and-fills.

I use a hand pumped suction device that will pull out 3-4 quarts then I add back up to 'full' (checking with engine running in park).

Do that once every month say until you've done 3 then you're good.