I've listed myself as "currently employed, but willing to be contacted." A couple employers have sent me messages. How long can I wait before responding would seem rude? Should I respond affirmatively just to see what they are offering?
3 days. It's my general metric for not needing to apologize, but in the current environment of high connectivity, some people will consider even a day to be slow. I refuse to stand by that particularly if I have made it clear that the communication channel is not my highest priority. BTW - I blow this frequently and end up apologizing.
In all honesty - if you've seen them and you are interested, respond ASAP. In this job market, a day can be too slow. If you aren't interested, but want to maintain contact, respond ASAP as well. If you are happy in your job and sitting there brooding about it... you may have your answer... you're not that interested.