Check the latest info from the FCC web site. The FCC auctioned off the 700Mhz band to the large networking companies (i.e. Verizon, AT&T, Sprint, etal.). That band included from 696Mhz to 806Mhz and killed all eight of my wireless mic systems. The next band to be auctioned off will include 550Mhz to 696Mhz but the move has been delayed several times because enough people are screaming that the FCC has balked on the move and left it on the table for now. In your case, I'd say continue using it until you no longer can.
Personally, I've replaced four of my 700Mhz AT and EV systems with four Line 6 XD-V70 digital systems which are in the 2.4Ghz band. My other four EV's all operate in the 640-670Mhz range and I'll continue to use them until the FCC says I can't. Replacing all these wireless systems was an expense dropped upon me by the Obama administration and I wasn't happy about it since the average cost was roughly $500/system for which I received no compensation and couldn't claim them as a loss, yet I was forced into the situation.
The trend is towards reducing and eliminating this heretofore widely used broadcast spectrum. I'd upgrade, and get out of any Mhz UHF frequency range as a long term plan, and switch to the 2.4 ghz range.
Another great option of the 2.4 area is the Audio Technica Pro 10. I have already bought two of the full systems and will be buying one more by the end of the year. So far they sound awesome and have been working for us great. I love the ability to take the unit out and mount it on a mic stand. If your not sure what I'm talking about give it a look on Youtube.
Our combination of mics are a lavalier and one hand held, two mics in one case.