I've been using a Medela mini electric (on mains power) 3 times a day for 3 months, and once a day (every day) for the 6 months before that. I borrowed it from a friend who had used it with 2 children (not sure how often, but she was working a few days a week from about 4 months). So personally I haven't had any complaints with its lifespan - might be different on batteries I guess.