I would like to suggest revamping the buff timer system for most buffs from a timer based system to a number based system.

Example:

Lumberjack buff lasts for 4 hours, when I use this, I pretty much feel compelled to at least make use of 2 hours of it without doing anything else. Instead of giving us 4 hours of this buff, maybe give us extra lumber up to a certain amount(for example 250 piece of lumber before it expires). This way, I don't feel obligated to do something while I have the buff on.

This happens with XP buffs too, a lot of times if I have a bunch of XP enhancing buffs, if I can't think of something to do exactly, I will actually logoff. Or if some dungeon/area is overcrowded, I'll also logoff instead of running to do something else.