I email my puppy's new family once a month for updates I love to see then grow up and become propre dogs, you'd all be amazed the number who dont reply then email me when they want the breeding restrictions lifting at 2 years
I always refuse and tell them if they cant be bothered to keep in touch with as ther breeder there certainly not having a litter from the pup I bred.
On the positive side I've met some very nice people who I'm in contact with all the time