Audio Lessons Learned - post your best advice for the newer members!

After puzzling out your budget and much reading and listening buy the best foundation pieces your budget allows (speakers, amp, pre-amp).
Buy them as if you're married to them ('cause you are).  

Purchase a source component(s).  These will undoubtedly be upgraded as your listening skills are refined. 
Don't chase the newest, bestest component.  Go Slow.

With apologies to Occam and his Razor......keep it simple!

It's a journey, not a destination.

Regards,
barts 

OP: Good to see your comments on McIntosh.  

I must say, I have done a bunch of upgrades over the last several years and the most impressive lesson I learned was how a good quality Power Conditioner can influence my sound.  Not just a surge protector, but a conditioner. 

My McIntosh MPC1500 was a phenomenal improvement.  I was using a Niagara 1200 and thought nothing of it.  Then, after the upgrade to the MPC1500 Power Conditioner the change was dramatic!!!  Took me a couple of days to figure out why the system sounded so incredible, then I remembered what I did.  WOW!  Still impressed by that component.

That still remains my biggest Lesson Learned over the past few years.

Understand how sound works. Understand how electronic components function (xraytonyb!). Get a good soundstage reference tool (Stereophile #3, Trk 10 on repeat is my current fav~PS Audio on order) move speakers symmetrically until soundstage goes as left, right, front to back as your system can make it go. Turning up your system doesn't make it louder if there's no bass, but it does blow tweeters (get a sub). Set the phase on a sub by feel, gently touch the sub surround and tower surround at the same time and feel the beat, adjust phase, repeat; fingers are more accurate than eyes. Trust your ears, if something doesn't feel right think about what that feels like and move or adjust; this is an exercise building confidence in your ears. All components from ear lobes inwards are unique to the current owner and cannot be repaired or replaced. Convincing yourself it sounds good and forcing your brain to recalculate stereo image is exhausting and changes if you go away and then come back. If the soundstage is as correct as the system can reproduce it will remain consistent over time. Some days sound is different than other days, don't always expect to feel it and cherish it when you do. It's about resolution. It's for entertainment. When I go to stereo shops and listen to their most expensive gear and don't hear any improvement in comparison to my home system it tells me a few things but I am still not certain what. Vinyl is smoother sounding at higher resolution but comes with a ritualism that borders on insanity, which can be entertaining. I'm trying to think of the best way to wrap this up. So here goes. There is dishonesty, mysticism, including some who have convinced themselves they know the truth and that includes me. At the same time there are accurate observations. It seems the only way to know the difference is to get to know the person making the statements and then make conclusions based upon your own evidence. Stay objective, use empiricism and repeatable experimentation. Be careful chasing rabbits. If it sounds good it is good. This is a list written by a lazy human.

Love the McIntosh love. I too have a system I’ve been assembling for many mc 500 c2300 and d150 dac are the heart of it with Tannoy Churchill’s. With all of that said, what really took mine to the Way next level was power cords and conditioners, and I’m not a shunyata salesmen so let me say what ever your flavor, give these things a try. You get quietness, depth, soundstage and things you’ve never heard out of your system. Believe me!

Speaker placement is the single biggest factor in getting the best out of your system. Search YouTube for examples and or lessons. Here is a good start  https://www.youtube.com/watch?v=84Pf0ycbyBM&ab_channel=RockyMountainInternationalAudioFest

Remember, most speaker designs assume being 2-6 feet from the back wall, so read the manufactures recommendations. There are many speaker today which are being design to be close to the rear wall just make sure you buy what your room allows for.

Minimum of one sub two is better 

This is personal but I have found a separate DAC had a noticeable difference. The output of a DAC in the $500-$1500 range will get you 95% of what is available from modern DAC's. In that price range you can also get it with a pre outs which help to simplify you system setup 

For Movies and surround sound an AVR works but for two channel stereo a dedicated stereo amp is the way to go, just make sure it does not have a DAC capability within it if you go with a stand alone DAC. Double processing is not the best.

Today a good streamer is worth while and there are many which are very good. Here are two examples of the concept

This one provides DSP capabilities and can send its signal to a Separate DAC
https://www.minidsp.com/products/streaming-hd-series/shd-studio
.
This one is the same as above only includes a DAC
  https://www.minidsp.com/products/streaming-hd-series/shd

Have Fun and Enjoy the Music