I used to start with grand intentions, and by the time Christmas actually rolled around, I had a handful mailed and a stack for husband to take to work (they distribute to each other--work friends-- in their work mailboxes).
The past few years, I've sort of dreaded the chore and tried to get by with as few as possible.
The kids are older now, and would be mortified if I tried to send out a "picture card" of them dressed in holiday attire.
I still have the cards I bought last year (unopened)... with no plans to open them this year. Until (most likely) husband comes home from work one night the week before and says, "I need cards for x, y, z and 1,2, 3"...
I like getting them, but I have enough "obligations" to deal with already, and don't like feeling obligated to add another thing. I do sort of like sending them to "old school" people (the parents of some of my long time friends, who aren't technologically inclined, for example), but as a general "to do" for a long list of people... not anymore.