How many times a month do you let guests play? If you’re already letting outsiders play through boxgroove, golfnow, or similar, it should be at least 3-4. I would always prefer a guest playing with a member to a random person off the street. Most local clubs are at 2 times/month, a few still at 1. I know of a local club with less than 10 family memberships, yet about half the guys I know there have wives that play golf. During the peak months, they play twice a month with their wife and beyond that play at Newport National, Meadowbrook, Montaup, etc. That’s guest fees, cart fees, and dining coming right out of club coffers. And come family budget and renewal time rest assured that it’s “his” membership, not “our” membership.
My intuition is that a club is financially better off allowing unlimited guest privileges as long as tee time restrictions are in place with a fairly high guest fee. If the person really wants to play without the member, prime tee times, have a handicap, tournaments, etc., they’ll join up at that point. If you’re already playing 30-40 rounds/year that should be a small premium over the cumulative guest fees. If you’re not, you probably won’t join under any circumstances.
One special I never see: actively encouraging upgrades of single to family memberships mid-season. For golf-only mostly male clubs this has huge potential. Offer to credit all guest fees to the membership — even better, once you hit the threshold membership should be automatic.