I generally ask a client who is the person, other than their spouse, that they trust most in the world and name that person as the executor/trustee - in a backup position to the spouse. It is entirely possible that the person you trust most is an attorney, but if they bill at 175-250 per hour, it is going to cost a lot for them to be the PR when they could just be the attorney for the PR.
In other words, you can save the $ and not name a professional. You can name two successors if you think a check and balance approach would be helpful.
Hope this helps. Elizabeth Powell