Do you consider cables to be a "component" of your system?

Definitely, I’ve had cables that change the whole listening experience for better or worse. Lower gauge cables seem to make a big impact. Going from 14/15 gauge down to something half that will provide so much more depth. A low gauge power cord, same thing. 
 

One thing that is supposed to really change things is doubling interconnects with a y splitter. I’m not sure why this is considered so effective other than halving the resistance, but the “Schroeder Method” as they call it has been a game changer for some.

I consider them as "accessories" . I have been making my own AC cords and interconnects for years now with great results. There’s some good DIY recipes out there that will cost you a fraction of a commercial available cable but still, it is not as cheap as one would think. I have also tried a few cables from famous cable brands with mixed results.

Cables can of course help to bring out the best of your components but they will never be a better solution than a component replacement. One lesson learned is to let a new cable burn-in long enough (>100 h or more) so you can really judge its effect on your system. What your hear on day 1 of using a new cable in your system will be very different after a few hundreds hours of usage. As someone pointed out, ROI on cables is a diminishing affair so there’s an equilibrium one must think about before spending too much on this adventure.

I purchased  a siltech cable burn in box approximately  a year ago. I personally  believe  that has been the best purchase  in hi-fi  I have made as far as sound quality  goes. Scary how much better a cable sounds after it has been left on the machine  for a week. Even cable  that I have run for twenty years and played the system every third night of at least two hours. After that many years and that much time by common wisdom  they should have been burned in but large gains after a week on the siltech machine.  Had audio connection  build me a lowercord burn in machine  ot arrived a week ago. I have a power cord on it now I will see what happens with it as well. 

At times I wonder when people  say cables don't make a difference  if they are running lamp cord for speaker wire and the free interconnects that came with a cheap Sony cd player back in the day. If so it is quite easy to see the difference  in cables when a person moves up to entry level hi-fi  cables. The first couple of hundred dollars makes a huge difference.  A person  doesn't  want to go to far up the wire line with more basic  equipment  higher the wire the more reveling  it is of the sound of the component.  Many  times a reference  grade wire makes a basic  component  sound bad but  what you are hearing is the component  not the wire. That is the skill in choosing  a hi-fi  system  is understanding  what is sounding  wrong and figuring  out what to replace. The other skill needed is to be able to eat your own personal  mistakes  and make changes just because  you paid money for something  doesn't  mean that it is good or that it is a match for your system.  Taking  your loss and moving  on is hard for many audio files.. 

Regards

I’ve updated my interconnects 4-5 times in 40 years. I’ve updated my speaker cables 3-4 times in the same period.  I didn’t really start with power cords until much more recently, mostly because everything I owned was hard wired.

All the best.

On a somewhat related note.  I purchased a ong run of an interconnect, used, and had them re-termed at the factory (Kimber in this case) to yield multiple pairs of shorter interconnects that I can use at a bargain price.  

The other method I've used is to buy the "older" generation of an interconnect just after the "New and improved" models are introduced.  I've saved 40% on new cables like this.  These tactics help take some of the sticker shock out of high end cables.  

Cheers