Before you begin, you must decide on whether or not to enable War Mode. War Mode makes it so that you will only see other players with War Mode enabled, which also enables PvP activity. Note that if you are in a party with someone not on War Mode while you are, you will be unable to see him or her. War Mode provides an experience buff as well as the enabling of three PvP talents that will greatly increase your power. Regardless of whether or not you enable War Mode, your objectives will remain the same in that you must complete all quest content to unlock flying later on and many of your War Campaign and Allied Race requirements. War Mode enables 10% bonus experience, 10% better rewards from World Quests, and allows for the gathering of Conquest points which can be used to buy gear. If you do play on War Mode, it is recommended to play with friends. Leveling without War Mode will not be significantly more time consuming.
That’s because armor of higher level has higher Azerite power requirements than lower level armor. That means a shiny new piece of Epic gear will have better stats but, unless you’ve been diligent about your Azerite power grind, won’t have as many traits unlocked. You lose options as you earn better gear. Eventually, you’ll grind out enough Azerite to earn those traits back, but you’re left with limited customization until then.
At 98 you have the option to drop what you're doing and return to your capitol city to start the quest for your Legion Artifact weapon. However, I do not believe this is necessary to do right away unless you're struggling with kill speed in your current gear. I would recommend waiting for a natural pause, such as hearthing to repair and clear your bags. From 100 to 107 you won't even really fight mobs that often; only just enough to clear the way to any treasure you need to pick up.
There’s a lot of #content in the new expansion. It’s mostly locked behind a variety of gates, some of which players can’t even control. Warfronts are the best example. You might assume joining a Warfront is a simple matter of opening the group finder. Wrong! Warfronts are only accessible for a week at a time. It’s not precisely clear how often that week will come around (it’s based both on a time gate and on the opposing faction gathering resources) but, as of right now, it looks likely to be available just one week out of every four.
For reference, my previous best time abusing Method-0 in 7.3.5 was 32.4 hours(as show in the old thread). A difference of just over 8 hours; which isn't all that bad, all things considered. And I believe I made several errors along the way, which could be cleaned up in future runs. I believe that that gap could be significantly closed by using a monk's bonus, but I hate playing monk...so...yeah. YMMV