I put a similar thread in 'General' before I realized it should more properly go here. My preferred solution would be that the timer only ran in instances, but the suggested list (including my own and some new ones) is:
- timer only run in instances
- timer run for a number of quests/chests
- timer to run for a 'number of XP'; ie. 20% bonus on the next 100,000 xp
My rationale for this is as follows: I've bought a few now, and I would guess that at least half of the total "3 hours" or "6 Hours" was wasted waiting for groups, selling, changing groups etc etc.
I don't think it's likely I'll buy more unless the timer only runs when I am in an instance.
Yes, I could plan my time in DDO with military precision, but a very positive part of the game is the social aspect. That, and the fact that getting groups can be frustrating already without being "on a timer" means that these XP/Loot Boost items decrease my enjoyment of the game overall.
As an example, let's suppose my FvS/healer has swallowed a potion and there is a group looking to run a quest that needs a healer. My FvS could join the group (making it more attractive to others since it has a healer), and wait idly as his timer runs down, or I could log in another char as a 'placeholder' making the group look odd. Or I could log in another char and wait for the group to fill having sent a tell to say "I'll join when you fill", which always looks greedy and lazy.