Noticed this one when triaging unanswered questions
As things currently stand, introduction era is a primary determinant in a unit's printed rules level. The rules categorizations in both TR: Prototypes and RS: 3145 NTNU show you when things shift Experimental to Advanced to Standard. A unit that would be considered Experimental on its debut in the 3050s is probably Standard in 3150.
per Ray from last summer:
It's all in the process of an overhaul. The old ('current') Introductory/Tournament/Advanced/Experimental system, just like the prior Level 1, 2, etc. system was too tied into the fluff and lore to really be a good breakdown of rules and gameplay level.
Informally, I'd classify it all as Introductory, Standard, and Optional. As it stands for the moment, Standard is anything in Total Warfare and the BattleMech Manual. The box sets are subsets of the Standard rules. The Beginner Box set contains the only real Introductory level rules. Everything beyond that, TechManual, Tactical Operations, and so on are Optional.
