If you want to to the vanguard quests and farm charr it can be good to do the quest a day later to keep the rmor buff.
day 1 hamnet, day 2 blazefiend
keep hamnet and farm charr, then when the blazefiend q is there you do the hamnet q, take reward and take the blazefiend q, which u also keep until the next is up and so on
Yeah this is what I typically do. Although I pick footman tate over blazefiend because melee charr hurt my Necro a lot and my imp and minions are too stupid to bail me out half the time. The stalkers and firecallers keel over pretty easy.
This is meant as an example. You always do yesterdays q. So you always have the armor buff and can farm charr in between the quests