If you're in the right window (footage not composition) then the Roto Brush should track for several frames. There is an indicator at the bottom of the Footage window. It will show an orange indicator at the starting poing and a green line for tracked frames. You start at the first frame, then let it track on it's own until it starts to drift or you run out of frames. Tracking is done by pressing the space bar. Now you make your adjustments. Roto Brush will now indicate the new frames that Roto Brush will automatically track. Double check the track before you continue and make any necessary adjustments. Once the tracking is complete Freeze and Render your Roto. If you do not freeze the roto at the end and you go back to the second frame to make a small adjustment you'll have to start again because this tool only works in one direction. New adjustments start a new track.
I hope this helps.
That's a great tip, Rick. Appreciated it!
Just today I did in fact go back to an earlier frame just to find out that I had to adjust subsequent frames all over again... :-/ So freezing will certainly help.
So would you click on the "Freeze" button every 100 or so frames or only when you're completely done with the adjustments and want to move on to the next task of refining the Matte?