Ok, so if it's one of your kids, then OK, they're going to get it in the will anyway, so give them a break on the price. But wait! What about the other siblings? Do you have enough cash to pay them equal share? It's the old making chalk of one... cheese of the other and you just can't do that.
Have you always felt sorry for that cousin that wants it now? Get serious! Did she / he consider your feelings the last time they bought a new car or flew to Jamaica without you? Charge them full pop!
Oh! It's the cute old couple next door who say they want it for their grandkids? Charge them extra if they draw the old 'we're getting on in years' card to get you to drop the price.
Don't let anybody play on your senses when it comes to selling your family cottage or vacation property. You are going to live to a ripe old age and need all the money you can get to pay your own way and not be a detriment to your loved ones.
...And besides.... you're the ones who had the good sense to keep that cottage until it became valuable enough to sell. It used to be that they couldn't give away waterfront property and now everybody wants it. It's an ace in the hole, don't give it away out of sentiment or guilt.