Couple of things, just make sure you note which cables came out of which holes on the old, then make a note of the legend on that socket as whilst you can usually rely on the colours of the wires you never know if a cowboy has been involved and just used whatever. The new socket holes will have the same legends to then put the wires into the right holes.
And as per power being off yes be careful, I swapped all the sockets in my house and had no issues except with one area, I turned off my downstairs sockets at the fuse box, but failed to realise that the kitchen was on a different switch entirely on the fuse box and got a nice little surprise when I undid the kitchen one. Lesson learnt by having nice tingly fingers for a little bit - which meant I got lucky.