The trouble with leaving discs at work is your work can be clobbered at the same time as your home (think of hurricane Katrina a couple weeks ago, and maybe Rita this week). The same goes for nearby friends and family. They have to be far enough away that it's not convenient to give them discs in person, which means using the mail.

Also, removing burned discs from an office can be difficult if you work in a security-conscious company, especially if your employment is ending for whatever reason. (We hired a programmer whose previous job was at a bank programming financial systems. When he gave them 2 weeks notice that he was leaving, they escorted him off the premises immediately and sent him a check for 2 weeks salary, standard procedure, nothing personal, anyone who was about to leave the bank simply wasn't allowed to touch sensitive systems or have other access to inside info).

Finally, friends and family are usually not willing to deal with stuff like getting crap in the mail and storing it, even at the level of just tossing the received envelope in a cardboard box and not losing it. It takes a preparedness buff (e.g. ETS inhabitant) who is into this kind of thing and thinks it's fun, or else ($$$$$) a professional who's getting paid for it.

Mailing discs is easy. You can get compact CD mailer envelopes that will hold up to 3 discs (that's why I chose the 3 disc maximum for recovery without special arrangement) and then just slap preprinted address labels and stamps on them and toss them in the mail like letters. So it's just a question of how often you get around to burning a disc. Yeah in practice I might do it just once a month, around the time I pay my bills and do other routine stuff like that. That's mostly because of the nuisance of burning them rather than mailing them.