Hatzflyer et al, I add 20/30 knots through the circuit because thats what works for me in my aeroplane. I'm not surprised if it wouldn't work for you in yours unless you fly the same type as me.
I didn't say that I would fly finals at Vs+20/30, only I would turn finals at that speed. If you're happy to turn finals at Vs+10/15 knots then good for you. If you're flying an aircraft with a normal stall speed of 40 knots and you fly a normal final turn of 30 degrees, your stall speed will be 43 knots. If you're flying at 50 knots, you only have a 7 knot margin. You may never get caught out by a gust/unnoticed change it the wind direction/miscalculated aircraft weight/etc and your handling may be beyond reproach during every last turn.
I prefer to be fast whenever I'm too close to the ground to recover from a spin as I only need to be slow for the bit where I touch down.
I generally fly a 1/2 mile final from 500' and thats plenty of room to slow down sufficiently to nail my landings every time on a 380 meter farm strip.