I have done a lot of domestic and Commercial work on Panels and have found that the original Electrician has left enough room and a couple of draw wires to pull future cables into the panel.
This is great, from my point of view, doing after-build repairs and the like.
Tell me guys, do you leave room up above a Panel in the wall and do you leave one or two draw-wires?.
Sure, it could help someone else in the near future, but it could help you in 5-10 years time too.
Another thing is also replacing the draw wire as it is used.
I had a Telecoms tech use all my draw wires to get his bundle of Cat5 wires down a wall next to the Panel, he never replaced a single one, there was 6 before he started!.
Some bosses call this sort of thing un-necessary waste of time and materials, but I have found that it pays off later on.
What do you guys think?