I think that one week is a good time to consider crossposting.  If you do so, please add links _in both directions_ so that people who read your question at either place will have a chance to know everything posted at the other place.  You can add a comment to the older post if you do not want to bump the question on the top page.

Since the FAQ entry about crossposting links here, I would like to express my opinion about something other than what is asked in this question, namely about crossposting in a short period of time (such as one day).  In my opinion, such crossposting is a selfish behavior and no considerate person should do that.  Of course everyone wants to get his/her question answered as quickly as possible, and exposing the question in many places increases the chance.  A person who makes simultaneous crossposts seems to think that his/her question is more important than other questions, but that is untrue.

Some new askers say: “But I am new and I do not know where the best place to ask is!”  So what?  Here are some of the obvious options in this situation:

1. Read each of the candidate websites for a week or so, and you will probably get the idea where the best place to ask is.  This requires time and effort.
2. Guess which is the best place, and try only that place.  If you do not receive a satisfactory answer in a week or so, crosspost the question at another place.  This requires minimal effort, and if your guess is not correct, it consumes time.
3. Crosspost your question right now.  _This does not require time or effort._

And they choose the option 3.  How is it not selfish?