How long will this mace last me?

I've been using it since 27 im almost level 57 and Im merciless and im still pretty much destroying things. Hitting for 2700 DPS single target I beleive 1200 with my ground slam.

I'm Lv59 and had been using this baby since I was 49:

As you can see, you could have changed weapon 10 levels ago; but then again, we kinda use what we get... So that weapon of yours will have to do until you find (or craft) better.

Mine was crafted; but when I later tried to craft a better axe with a superior kind of axe, I realized how lucky I was on this crafting; since even better weapons with +20% Quality and +100% Damage were still doing way lower DPS because of the lack of the double +Phys modifier (and speed on top of that).

My single target is Heavy Strike using this combination:

It does around 5750 DPS, +7000 when using Hatred, but lately I go with the Determination (armor) Aura mostly...

So... The answer to your question... It will last you until you find better; and you could have done so (if lucky) 10 levels ago.
Just don't let you fool by the color of your mace making you ignore blue or yellow weapons with more DPS, since yours kinda only has +19% Stun Duration if you discard the DPS itself.

Yeah i've yet to find another mace that has been better sadly =\