Depends
What specific sites your linking to.
Why your linking to them in the first place.
How your linking to them, (naturally, as sponsors or sold links, etc)
How relevant are they to your site?
How useful are they to your visitors?
What deals are in place from the fact your linking?
WHat will you lose by not linking to them.
Why change what your linking to if your site is doing well in SERPS?