Hi,
in many renders i have some areas totally clean and many others with some noise.
A fantastic feature could be a lasso render region (ideally with add areas selection) to resume last render and work only on noisy areas.
Many thanks
Stefano
+1 but for me just a basic render region would be good enough for now.
X2 on the region render. Good technique, when troubleshooting or post would take too long.
You shoud post your request to appropriate bord if you want to make it valid ;] Moving to feature request.
lets see if the current solution is enough 
moving to resolved