It depends on what you want. I had one for 3 years and moved the credit line to the World MC and closed it because the Signature card only reported the High balance. I never used any of the benefits that came along with the card. Because I already have them on other cards.
If you want your limit to report, keep it, if not, don't. Asking for an increase will not factor into your utilization due to the limit not being reported.
