It is often difficult to keep that all in mind, though. It takes real effort to track the world outside of the PCs. I am not saying it isn't worthwhile, btw -- just that it is hard.
I actually find that fun and not at all difficult.
I find listing them (the expected changes) and making notes helps.
I've got 4 Clocks running concurrently (4 APs, listed 3 here) along with their respective Adventure League Material.
Here are some of the items that I keep track of which may influence various NPCs the party interacts with.
Tyranny of Dragons Clock
Council gathers in Waterdeep which becomes quite the hub
Price of weaponry increases sharply as a war with Tiamat and her forces is imminent
Armourers, Bowyers/Fletchers, Smiths, Dracologists, Arcanists...etc are in demand
Magical items are actively sourced by the Council and turned into residuum to create teleportation circles in order to prepare for the movement of vast armies across the Sword Coast
The sightings and tracking of dragons, particularly chromatics leads, lead to wide speculative conspiracy theories
The Emerald Enclave provides the effects on natural life the Draakhorn is having and this is corroborated by livestock and pet owners.
Influx of mercenary groups
Religious gatherings/cults spring up spewing end-of-days scenario and the "gods have abandoned us"
Town criers and news pamphlets become common place
Messengers and diplomats work overtime as the Council requests ex-Lord Alliance members join the fight against Tiamat
Artists and bards craft works of art (for sale) and compose odes respectively about the Champions of the Council (the PCs)
The Council uses some of the above for good-PR
...etc
Storm Kings Thunder Clock
As per some of the above,
Wares becomes increasingly more expensive with the giants acting out throughout the North
Refugees from farms and small undefended homesteads seek out larger centres for safety - as the metropolises become overcrowded
...etc
Descent into Avernus Clock
As per some of the above,
With the powerbase of the Order of the Gauntlet compromised, the faction is on the verge of withdrawing from the Council to deal with the disappearance of Elturel
The disappearance of Elturel emboldens the doomsday cults with their rhetoric and conspiracy theories
...etc