Brand matching important for cable?

I am building the audio video system and currently at the stage of upgrading the cables. I have auditioned 3 brands (matching brand and series) on the speakers i intend to upgrade later on.

How critical is it to match the same brand or even same series of power, xlr, hdmi, and speakers cable? Dealer basically told me it is best to match all cable same brand and same series. However, I like certain brand on xlr while other brand on speaker, hdmi and other on power. My current system at current stage.

Mcintosh MC205
Mcintosh MC601 x 2
Marantz AV8801
PS Audio P10
Oppo 105D player
PSB Image T 5.1 system. (Will upgrade to Magico S5, S1, SCC)

Cables in my liking.

PS 10 Power Cable - PS Audio AC12
Amps Power Cable - Shunyata Etron
XLR - Audioquest Earth
Speaker Cable - Audioquest Aspen for front 3. Rocket 44 for rear 2

Please kindly share your opinion. Thank you.
What a surprise, a dealer recommending using all of one brand of cables. Jeez, wouldn't it be great if that dealer actually carried that great brand. Haha.

Some will swear by using the same brand, but that's not mirrored my experiences. Use what ever works for you. Don't be afraid to try other sources, like The Cable Company.
Trust your ears! If all one brand works for you, go for that but if you like a mix and match better, that's what's better for you!

I use speaker cable from Analysis Plus, interconnect from Harmonic Technology (XLR), DH Labs (SE), and yet another brand for SPDIF cable.
In last 45 years I've tried every thing possible.
For the vast majority of sane people , which leaves me out,
all one brand is way to go.
If you want the best you need to swap everything out one cable at a time, give it a week anyway to settle it, and try the next and the next with at least 3 or 4 of the usual suspects you can afford.
If you are diligent in about 6 months and X thousand $$$ you'll have your answer.
Only thing I think I know is mid-line up Analysis Plus IC's on main source give you best foundation on symphonic music.
But the speaker cables are bit to diffuse for symphonic etc etc etc etc .
Schubert, when you refer to "the vast majority of sane people", I'll assume that you are referring to those that buy their audio equipment from Best Buys?
Well some on here aren't totally nuts like me.
Yeah bottom line is you have to make one change/switch at a time and assess. Often after due course you'll get the hang of what various lines do in general and might end up settling on one preferred product/approach. Or not. It's the process that matters most not where you end up.
I will second, or is that third placing in one new cable at a time. I have always had Purist Audio in my system as I personaly just like the sound. I have always have / had top of the line or near top of the the lines cables from them until recently. I wanted to go one notch up in their speaker line ....until I found out that it would cost me anywhere between $10,000 to $12,000 plus my current Purist Cables. No way, I looked and I looked and listened and ended up with the Cardas Clear Beyond Speaker cables .... what a nice addtion at about $4,000-$5,000 in savings. Real good cables that just compliemented the rest of the system and the Purist Cables. So, I never mixed and matched cables until now ...and I am glad that I did both sonically and financially as it was the right move. Now ....I have no idea what the system would sound like if I added a Cardas Clear Interconnect ( as there is no Clear Beyond interconenct ) at about 40% less than what I paid for my Purist Audio Interconects ......
"However I like......"

It's your system. You have answered your own question.
This question has been discussed in a number of past threads, including this one and this one. (The subject of the latter thread initially was power cords, but as you'll see it evolved into a broader discussion of cables in general). As you'll see, and as is often the case in audio, there was no clear consensus.

My comments in those threads were summarized here. For the reasons I stated, from a technical standpoint the so-called "loom theory" (a belief that it is necessarily or at least likely to be best to use cables from the same manufacturer throughout a system) IMO makes no sense whatsoever. Other opinions will certainly differ in some cases.

-- Al
I think in some very rare cases the "loom theory" might have some merit but in the overwhelming majority of cases it's meaningless. So agree with you 99.99%.
I'm sure most manufacturers and dealers love the "loom theory" though. I would too. 8^)
AL, Brisson at MIT seems to claim because IC and SC "roll off" at different Freqs , you need to match the two.
I say seems to because I may well be wrong about what he says, kinda fuzzy for my old brain.
Is this possible?
Also, for any given human THEIR brain is the ultimate reality. Placebo's can't work, but they do, if your brain/being tells you something sounds better that is not an illusion but bed-rock reality. The fact the brain may be doing so only to maintain your mental stasis is irrelevant.
Can it also be that we do not and never will know but a small portion of the Variables?
Hi Schubert,

I can't envision any reason as to why the match or mismatch of IC and SC bandwidths (essentially the upper limit of the range of frequencies the cables can pass without significant attenuation/rolloff) would be of any significance.

Also, the upper limit to the range of frequencies an IC can pass will vary significantly depending on the output impedance of the component which drives the cable. And in most cases the bandwidth of both types of cable will be (and should be) much greater than the bandwidths of our ears, the speakers, and usually some or all of the electronic components. Which means that what those cable bandwidths are won't matter, because other things will limit the overall bandwidth.

That said, though, I can't speak too knowledgeably about MIT cables in particular. In part because I've never seen a clear and technically meaningful definition of what Mr. Brisson means by "articulation poles," and in part because I've never seen a schematic or other technical description of what is in his network boxes.

Regarding your post just above, I agree. I would add that even in the case of many variables that can be identified, such as many of as those I listed in my post dated 12-15-12 in the thread I linked to earlier, the resulting sonic consequences, if any, will in many cases have little or no predictability. The effects of electrical noise and RFI on the sonics of a component being one example.

Best regards,
-- Al
Glad I'm not only one who couldn't get what he meant.
MIT does sound different though, what I THINK I've heard a time or two on MIT SC's was a stop like a car hitting a brick wall at around 50Hz with speakers than I had heard in same room go down to 30's . Seems like this might affect harmonics etc above this to my feeble brain.
It ain't necessarily so, or as others above have stated, go with what sounds best. Remember this, most cables are tone controls for a system that has colorations in one form or another and there are no absolutes, only what sounds best to the listener. I sure wish things were a bit more linear in approach but unfortunately when it comes to reproduced music there is no sure fire direct path to the absolute sound, only personal experience and what sounds best contrary to what others might have you believe.