Is it realistic to say that there are +/- 4 years from start of one expansion to the start of the next? I took a guess with Anduins age in MoP, which I guessed 15. And from there I calculated back- and forwards.
BC - 3 years
WotLK - 7 years
Cat - 11 years
MoP - 15 years
WoD - 19 years
Legion - 23 years
BoA - 27 years
Shadow - 31 years
Dragon - 35 years
Blizz has already told us canonically (at least until they retcon it) how long expansions and the time between them is.
Taken from Wowhead after a forum post by Steve Danuser (narrative director of WoW): -
Year
Duration
Expansion
0
Opening of the Dark Portal
0 - 25
25 years
Events of Warcraft 1, 2, and 3
25 - 26
One year
World of Warcraft
26 - 27
One year
Burning Crusade
27 - 28
One year
Wrath of the Lich King
28 - 30
Two years
Cataclysm
30 - 31
One year
Mists of Pandaria
31 - 32
One year
Warlords of Draenor
32 - 33
One year
Legion (Four years after the end of WotLK)
33 - 35
Two years
Battle for Azeroth (Anduin’s age officially stated as 18)
35 - 37
Two Years
Shadowlands
37 - 40
Three Years
Time Skip between Shadowlands and Dragonflight
40+
Unknown
Dragonflight
So as it stands Anduin is 25 at the start of DF, since he is stated to be 18 after we’re done with the Argus Campaign.
Edit: That is, provided that there’s no temporal shenaniganry going on, as some realms experience time differently, with Turalyon and Alleria experiencing a thousand years with the Army of the Light while only decades passed on Azeroth.
Blizz generally avoids talking about how much time has passed between the various events, but for the rest there is little to contradict it outside the odd voiceline talking about years of downtime. So technically speaking it’s not a contradiction, if they never established it to begin with.
In WOW kind of RPG s or similar stuff (D&D , LotR etc…) Even in the old times , most of the intelligent beings are not measuring the years but the seasons that are passing… so I dont know if they are celebrating birthdays or such stuff… but the aging is mostly something you can observe i believe… and also there are many factors in the universe of Warcraft that can affect such ageism.