The sibling commenters here have it right -- and I'll add that reviewing and similarly reading grant submissions are tasks that benefit the researcher as well.

The sibling commenters here have it right -- and I'll add that reviewing and similarly reading grant submissions are tasks that benefit the researcher as well. Sure, it's work, but you stay on top of the new stuff in your field, develop some sense of what's important and what's minutia, are able to identify new people coming into the field and how they or their work might interact with your own. If you don't review at all, you are actually missing a fair bit of professional development and power. It works fine for some not to review but for others it's an important part of the intellectual process.