We started with RedGate Monitoring and added all our SQL Servers. As a result we consumed too much licenses. Although there's a warning on the top of the screen for this, the unlicensed servers are reporting 'healthy' which is a little tricky (especially for non-dba it'ers) because you don't know the state.

I like to see the unlicensed servers in a different color ( for example gray) to see a better reliable overview