Supporter suggestion

I have recieved some complaints from Supporters on my WPMS site. These are people that doesn't have a subscription payment but chooses to pay for different periods of times depending (I guess) on current personal economy. Their complaint is that there is no warning when their Supporter period is about to expire.

So my suggestion is to include an optional message to users where they are reminded that their Supporter period is about to expire and that they need to make a payment to continue being a Supporter.