Is it possible to really know what you're doing?

Finding balance and perspective can hard for people who have the discretionary time and money for audio.

Sometimes when I find myself obsessing over audio, I look at other parts of my life and the world and suspect that I could be doing other things. Maybe even helping others. It helps restore my confidence that my audio is good enough. 

Our understanding and proficiency is increased when spend time with anything ... but do we ever know what's really going on?  No.

I think the OP is alluding to whether there is a holistic approach to system building, rather than trial and error. Sure there are some basics in terms of matching power/current needs from amp to speakers and some impedance/gain issues in the entire chain, but for me, I cannot look at specs on paper and conclude that a given set up is going to sound "real," leaving aside the room and set up of the system with a given room (the acoustics part, rather than the electronics/signal part). 

I built my current main system through trial and some minimal error- improving what needed to be changed to get it closer to my ideal. Some of those improvements might be regarded as "lateral" rather than "upgrades" based on price, others (like turntable isolation) were done of necessity, still others based on my experience from past set ups (electrical power).  I already knew a lot of what the core components did well and where they were lacking in this current room set up so had to learn how to take better advantage of a new room. Some of that experience told me what tubes I preferred in certain positions in voicing the system but these were refinements based on long experience with the particular gear in combination. The system is "tweaked" to that degree and a change in phono cartridge from a few other "high end" brands to another one "brought it home" that last iota--which was only revealed once everything else was in sync. 

This still leaves me with the conclusion that I have no universal approach to system building in the sense that I can take the abstract at a given budget for a particular room and apply a view or philosophy that will yield a predicted result with a given combination of unfamiliar components in a given room. Instead, it is listening in situ in a controlled environment that has enabled me to assemble and optimize what I had.

My vintage system, based largely on 50+ year old components which I have owned since they were new, is in some ways, more forgiving and I was replicating what I had in place in 1975 (with a few substitutions). But, though that system sounds great for what it is, it represents a "time capsule" system and not an attempt at state of the art reproduction (though it can be very convincing on certain program material). 

@emergingsoul Within the interest in audio equipment there are only a few things that matter.

The First is how one Weds to the Source Material, are they a Tape, Vinyl Album, CD, Streamed / File user.

The Second is whether one is Monogamous in their being Wed to a Source Material, or if one is Polygamous in how they Wed to a Source Material.

Then what matters, is whether one is content with only one version of the Source Materials embedded data being extracted and sent or if one is content only when being able to have a selection of options on how embedded data is extracted to be sent.

An embedded data once extracted is speedily converted to a electrical energy to undertake a Journey where the electrical energy will be Amplified / Gain Added.

The electrical energy is to travel through a selection of devices used to add additional Amplification / Gain. Electrical Energy is not beamed it needs a conduit to travel both within a device and external to a device.

Each Device and Umbilical used as the connection between devices are quite Capable of adding a trait of the design that will be detectable as an audible influence. 

The Experience being anticipated once the Data is extracted is End Sound, usually in the form of Music.

Downstream of the Data extraction any device used to manage the electrical energy / sent signal has the capacity to influence the End Sound to be produced.

The Speaker which is the only device in use downstream of the embedded data being extracted and sent, is the only device in the set up able to produce sound.

Speakers have a vast range of discernible differences in how a End Sound is produced and being perceived as a Sound. 

Why would a person be Monogamous in relation to devices and ancillaries used to create a Audio System. 

Why would a person be Polygamous in relation to devices and ancillaries used to create a Audio System.

For myself locking myself into a marriage of one choice of devices makes the audio experience bland, the option to intervene and produce End Sound that stands out for its qualities, but delivers an injection of a differing to the influence on the End Sound, is where I am most content as an enthusiast of creating Audio Systems. 

In Audio being Faithful to a intent for a systems creation or to a Philosophy of how a system should be produced will supply a very satisfying musical encounter.

It also limits exposing oneself to experiences and broadening the learning through extending the musical encounters that can be had, which is a commodity most with an interest in audio equipment seeks out.

You don't have to know anything, you can just pay somebody who does know.  There was a time when that was the role of the audio dealer.  Now people are into the "journey" and want to make their own choices.  Some people quickly figure stuff out and others wander thru the desert.  At some point it really doesn't matter because we're not designing commercial aircraft where mistakes can cost lives.