I have just done a clean install and it took 69Gb plus 17 Gb fornthe recovery partition, and asked for an overprovisioning section of 46 GB ( the performance setting for Samsung)
Note Photoshop and DPP are not even loaded yet.
So its going to be 150GB!
Personally I would definitely go for 500GB. If its your only disc or 256GB just fornthenOS and applications.
Might cost you £70 more but you will use it. IMO.
PEBKAC. Turn your overprovisioning back to 10%, even 5% is fine. 46GB is insanely wasteful. Turn off magician, it doesn't help - the RAM acceleration only helps benchmarks, not real world.
I have Windows 10, Office 2013, Photoshop and Bridge CS6, a bunch of utilities, browsers, and random stuff : total 36GB. That doesn't include a hibernate file (disable it as here) but does include a 16GB swap file. I have 91GB free on my 120GB SSD.
What I don't have on my disk is data: no images, no caches, no iTunes library, no browser caches, no old installs of Windows. If I did I might half fill my 120GB SSD. Also hit start and type "disk cleanup", let it run, click "clean up system files" and let it run again. That can clear out a bunch of crud.