Brushed motor maintenance advice?

[pete2222]

Can anyone advise if I am just running it in my garden and the street, how much life am I going to get before I need to worry about changing brushes or any other maintenance. At the moment I quite like it. It seems pretty smooth, and responsive.
Most of my experience so far with 1/10th scale has been with brushless. However, after some recent speedo problems, I’m now running an old brushed motor in my B4. A stock 27T.