l preference. And also remembering that if there is no treatment in your studio, the monitors will not be used correctly..
there's a lot of mythology about how much treatment you'll find in the average commercial control room or post room.... the fact is that apart from some very swanky places that are big enough for film work or mastering labs, high end ones, that are treated for a fairly narrow sweet spot in a purpose built room, even places with bass traps, diffusers etc are kinda thrown together. If an actual acoustician is involved they make compromises for a wide 'sweet spot' to acomodate the client and help the engineer hear when he's wandering around setting up hardware controls. Those needs limit what can be done anyway. The level of treatment is having most effect when the sofit mounted speakers are blasting to impress the client. If you're working alone the first rule is don't turn the volume up much. Only to make sure your bass isn't louder than you think it is or isn't overcompressed where instead of getting exponentially louder as you turn up it actually never gets any louder as you turn up ;-) even then just for a sec to get relative levels. If you mix low you don't hear the amplification working, you avoid ear fatigue and you don't run much risk of creating nulls, standing waves or just driving the room resonance. These are best practices everywhere you go. If you don't have an SPL meter then download an app, there are a few for free that are very good. Even a nice commercial facility tends to have a sound in the control room. A good balance engineer avoids mixing into the room whether its at home or in a swanky commercial space. Oddly, one of the best studios left in Philly where I live (the city, not the studio) has a highly treated control room for tracking where the rare neve desk is and a few choice pieces of gear.... then past the machine room where the studer and ampex machiens live there's a spare vocal booth that's half closet and then the post room. The post room ahs a gorgeous SSL G and all the really good outboard like bluestripe 1176es etc. This room isn't very treated if at all. Magical things come out of there. The less you know what you're doing the more treatment you need. I've been back there with the owner (grammy winner, not name droping) and he monitors hella low and knows his space. I think he's using a pair of NS10s and a pair of questeds or something like that.
I think a lot of places make the treatment colorful, put up pointless wood panneling etc just to impress the client, its heping but not that much. especially in a boxy control room. If your room is boxy and you're worried the first thing to do if tis already carpeted is to consider getting the ceiling out of the equation, this is the only time auralex is worth a damn. Corner traps and diffusers can be made from cheap materials at the hardware store. Really the drywall and shape are most to blame and that's hard to change. Its the rare studio that has a non perpendicular control room with a slanted ceiling like a mastering lab.... go look up peerless mastering or the lodge and look at the shape of those rooms... that's treatment. Everything else is a bandaid. Others will disagree.... but take a look at some studios of old, the mom and pop labels like motown in berry gordy's basement or sun? you going to tell me those records weren't good?
edit: I also want to point out that deadening your room is a bad idea too.... if you've ever been in the dead room somewhere its pretty creepy and its going to really throw you off. Building broad traps, diffusers, putting down tick carpet and auralexing the hell out of your side walls and ceiling will probably be too far towards dead without solving the problem of decoupling your floor and decorelating the walls which is another story entirely, an architectural story.... great for recording a really dry signal but not where you want to make a balance, my young friend. Make peace with you speakers and space, then develop best practices to work effectively in them. Know your tools, whatever they are, from the recorder (DAW whatever) to the compressors and equalizers you have at your disposal, really understand those problem solving tools.... and then have fun and stop worrying.