This is my first attempt at a guide and to be honest It's really just a build guide, I found that i read over 20 guides for Dr. mundo and still ended up playing my own style, I truly do suggest playing a style you create

For farming in lane, I would save your cleaver for last hitting minions, 25ish gold is still 25ish gold, and you Regen the HP it costs very quickly with your passive. I find Burning agony to only be a good ability if you enter into a massive fray of minions and are good on HP. do note though however that the HP cost is very low and by 3 items in you will likely Regen HP faster then you lose it.

Let's face it, we all have bad games where we seem to always be running, just remember that if the chasing party has stuns,slows, or debuffs like that to activate Burning agony, it reduce the duration of those debuffing effects by a good 35% that with merc treads makes about 70% making you almost unslowable and also making you an excellent runner, don't forget that your cleaver slows the enemy, so a well aimed and timed cleaver often will save your life.