OP, what is your system? Power cords and interconnects can make a big and obvious difference.. but it is dependent on your system and your objectives.
Perhaps (it sounds like this) you are largely happy with your system and just don’t want to feel like you missed something. That is fine… I’m not sure if I were you I would do anything. If you really want to get the very best sound (assuming you have pretty good equipment), then you have to be prepared to work for it. Like do some reading and rent a couple sets of high end cords from the Cable Store. Then do thoughtful comparisons. If you try some really high end stuff… even if you don’t want to buy it, the experience can tell you what you can get out of doing it…. a tiny change, or huge. You can direct your further work from their. Typically I would start with speaker cables and interconnects… but they all can make a difference.
If this doesn’t appeal to you, the buy a budget cord an feel good that you covered your bases.. or don’t and feel good that you didn’t waste the money.
If you live in a multi family building, I would guess you can be certain you do not have good clean power. All the appliances and stuff in the building conspires to mess it up.
