Hiya!
Self-Proclaimed Grognard here...
From Cook & Moldvay, in adventure module "X1: The Isle of Dread," written for the Expert Rules boxed set (the 'E' in my beloved BECM edition):
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Absolutely. This falls into the Basic books "BE FAIR!" directive.
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The error I have seen DM's make is "It's a door", "It's a door", "It's a door", "It's a door", "It's a slightly purple door with the iron bound straps looking like they were sort of sub-set into the wood. It also has a slight glisten to it, like dew on morning grass. "It's a door", "It's a door", "It's a door"...etc.
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Basically telegraphing "this foe is beyond you...". Which, from personal Player experience, completely destroys my sense of "I get to choose for my PC", because I now have information I never get except when the DM wants to say "Oh, this monster will kill all of you. Don't go that way".

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So, while I agree with the advice, the DM has to take care to "be fair"...and in this case, it means trying to give roughly the same 'amount' of information when describing things, unless the Players specifically states an action that would give them more/less info.
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At least that's how I've interpreted it in conjunction with other advice.
And also:
History became legend, legend became myth, and some things that should not have been forgotten were lost. I appreciated the reminder this morning...I need to keep this in mind more often.
Yup. Another prime example of why re-reading the "boring" parts is always a good idea!

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Many DM's just read the 'rules' when they come up in play. They never spend the time to read all the other 'boring stuff'. "I need to read the Initiative and Two-Handed Weapons section", but "...meh...I don't need to read the section about coins and economy". Often it's in the sections that DON'T have anything to do directly with the PC's capabilities that get's overlooked out of a desire to "get to the good stuff" (re: combat, big plot twists, important NPC interactions, etc).
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Worst...todays "adventure modules" tend to try and encourage the same mindset: "Ignore the boring stuff...get straight to the EXCITING stuff!". Yes, Players, and the DM, need to be excited about playing the game...obviously...but when you sit down and the game starts with an explosion, followed by 39 more explosions, well, after about the 4th or 5th, it's no longer "exciting"...it's just expected.
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The rest of this thread has more great advice! I still go back to the back of my Basic Book (Moldvay version; 1981) once or twice a year and just re-read the "Dungeon Mastering as a Fine Art" part.
^_^
Paul L. Ming