For how long can I leave my 7 week old in a vibrating bouncer? My daughter has colic, and the vibration seems to help her a lot. But I'm concern about leaving her there for long periods of time, especially if she falls asleep.

Babies are meant to be held a lot, and they learn from being in your arms and up "where the action is" rather than spending long hours in any device such as a bed, playpen, carseat or bouncer. Since the vibrating motion of the bouncer calms your baby, I think it is OK to use it occasionally, or even daily for short periods, but I would not advise you to leave her in it for hours at a time. Any baby that is left in one position for hours at a time is at risk for changes in posture and head shape (flat heads from spending hours lying on their backs, for instance) as well as missing out on the human interaction that she would normally get from spending lots of time in your arms. I do not think that the vibration itself does any harm, just the lengthy periods alone in the bouncer.

Consider "wearing"  your baby in a sling for part of every day. Just be aware that recent information has come out about the dangers of pocket type slings for very young babies; some have had their breathing compromised by being placed in a sling so that their face is obstructed or their chin is forced down onto their chest in an unnatural position. When used safely and with common sense, slings are very useful tools to keep your baby happy and close to you where she can benefit from the stimulation of being part of your daily activities.