Much like a Californian Mountain Lion, there is no way of dressing this one up.
Power supplies. They may not be the most exciting purchase you'll make all year, however spend the time to get it "right" and you'll save yourself countless headaches in the not too distant future.
You see, everything in your set up, in some way, affects the sound that comes out of your speaker and eventually into your ears. Now if it's cool things, like trusty overdrive pedals and gargantuan valve amplifiers, the thing that is most obviously affected is "tone". If it's not cool things, like power supplies and compressor pedals, then the thing most obviously affected is background noise or hum... OK compressor pedals don't necessarily add to background noise but they're still not cool.
Now in fairness, all the building blocks of your guitar "rig" ( guitar pickups, pedals, amps, speakers, leads etc ), in some way add to the aforementioned hum but a poorly designed or unsuitable power supply can REALLY crank the white noise up! It's even worse if your set-up is placed in the same room as a dimmer switch!
But which power supply should you opt for and how much should you spend? If you've ever caught your internal monologue saying something like "Hey look at this pedal power supply I've just found on Amazon!? It powers up to 28 pedals and costs the same as Greggs Steak Bake!", then take the internet away from it, immediately. Those "Too good to be true" units are a one way ticket to "Buzzy Boulevard". Save your money in the long run and invest in a proper, isolated power supply from the likes of Voodoo Lab, Strymon or MXR. Make sure your chosen unit has enough outputs and that those outputs supply enough milliamps for the appropriate pedals ( delays and reverbs are usually the pedals with the biggest current draw, with overdrives and fuzzes usually only needing minimal currents ) and away you go.
It may not give you the instant gratification a boutique fuzz box can, but it's a must have for any pedalboard worth its salt. After all, you wouldn't buy the Ferrari of your dreams ( 365 GTB Daytona, thanks very much ) only to go and put budget tyres on it now, would you?
See ya soon!