how much hit do we need

... or build two sets of gear, one for raiding and one for dungeons, which is what I do, and have done for years. When you get an upgrade, think about maybe moving the bit you replace to a threat set for heroics, maybe with a reforge or re-enchant. It's not like you need a full set of 378 gear for troll dungeons.

And it is much easier to get threat capped for 5 mans (at least trash) than for raids: gear against level 85 mobs rather than L88 ones. Getting 5% hit and 20 expertise requires only a modest sacrifice in survivability - use a hit trinket instead of a stamina one; wear a couple of tank pieces with unreforged expertise and you should be set.

I know not all mobs in 5 mans are level 85, but on the tougher ones - notably bosses - I don't find threat an issue (maybe it's vengenance, maybe it's that with only one target, dps are hitting what you hit).

econ21 wrote:wear a couple of tank pieces with unreforged expertise

You can go one step further and reforge your old tank gear into exp/hit for your threat/heroics set. If you're eng, you can even regem your hat cogwheels to exp/hit (or make a second hat).

Now that i think of it, it WOULD make sense to have something that reduces the boss's chance to parry or smth.
As a tank your prolly pretty used to having to hit a boss in the face, after all those hours, maybe making you better att hitting where the boss wont parry?
Still not saying we need it, but it kinda could make sense atleast?

I find hit sets also very helpful in raid fights like Rhyolith/ Beth'tilac where you have a lot of adds flying about and it is increasingly important that the moves you use to collect them actually connect as your taunts are sometimes on cooldown from being used for something else.

More than 1 set of gear seems like the optimal solution, then the decision comes down to what situations require me to have a bit more hit or expertise?

Don't Forget hit/exp food/elixirs.

I have been thinking about wearing some hit and expertise gear since I don't raid and only do heroics. Isn't there a hit trinket from the Tol Barad vendor? You could just wear that when doing 5-man content.

Only for casters...
but License to Slay and Heart of Rage are really sexy for a threatset.