Hot n Pot
PoT is most powerful when you are low level or on grinds. Once you hit 60 though and if you want to focus more for raiding purposes then it becomes less effective. To break it down...
25 PoT means 25 power per pow tick(6 seconds)... so that means 125 pow every 30 seconds. Being a sorcerer that means it would take over 2 minutes to accumulate enough power for just one more of my mca nukes.
I'm not saying PoT isn't important or powerful, but at the high end of the game if it comes down to between that or a stat heavy or pow heavy item (or in this case CM) I'd rather go with stats and power. Most raids don't last long enough or you don't live long enough for PoT to pay off.
I'd definately buy the first 1 or 2 levels of focus and mental clarity though. Worth it while they are cheap.
Dueling or Farming
I bought 125 cms worth of hot while leveling up to 55 on my tank. It was great and helped on grinds and farming. I looked at it as a cm investment so that when I needed to grind cm for my mca, all I needed was 75 cms then I reallocated first time and used the 125 + the 75 cms and bought my mca. As others have said, if you plan duel or farm or solo then hot makes sense, but if your going for a MT build, then there are too many other more important cms to have than hot. Hope that makes sense.
Any HoT you aquire via cms will stack on top of each other and with gear. If you buy a cm that gives +4 HoT, and then another that gives +4 HoT, you will have a total of +8 HoT
As for gear, its a little more tricky. LIke the example from earlier in this thread, If you have 4 Hot items on (20,20,20,20) you will get +20 HoT for the first item (or full HoT), 10 from the second item (Half of the Hot its rated for), and 1 HoT for each additional item after that. So for gear that has 80 HoT rating, you will really only get 32 HoT total from those 4 peices of gear. Now if you take the 32 HoT you have from your gear, and add in the 8 HoT you have from cms, you now have 40 HoT.
You have to consider your natural HoT as well. The HoT that you get from CMs stacks with your natural HoT (obviously). My 40 tank has 32 HoT from CMs at level 40, and it's awesome. Coupled with my natural HoT, I have about 140-150 HoT altogether. It helps a lot in both grinds and duels. However, I'll probably delete them in the high end because I will be raiding more than dueling and IMO, HoT is not for raid..
I look at hot for a tank like a bard's heal. Its not going stand up under alot of pressure, but it sure is great when grinding. It also allow for alternative groups such as a tank with a high hot and good Agi, and a blood nec or a bard in the group can tear up yellows-drk blues non stop. My strategy when building a tank is to buy as much hot as I can, then reallocate those cms when you hit 55. Basically you get the usage out of them when you need it most coming up the levels, but when you make the transition to filling a more significant role in MTing, Reallocating those CMs for more important things is the right move. A good example of this is hearty 3. Almost a must for tanks...but you can't buy it till 60. So why not use at least hot 1 and 2 then use those cm points to purchase that ability as a fair trade. Makes sense.
two other reasons to get hot before reallocating at 55, is cost factor for food and it increases speed of xp. Though the food cost is not much to write home about, the speeding up of xp is signifigant. 1 if you do not have a healer it takes less time for the tank to recover and xp to continue and 2 a healer is able to use smaller heals so they in turn do not draw as much agro to themselves and also allows them to get into the action with some dmg casting as their power isn't being used up constantly in heals.
For many reasons hot makes good sense from lvl 1-55. I always play a tank and my wife plays healer, and I cannot tell you how many times she has stated her distain for characters who don't have any hot whatso ever. If you really want a good answer to how good the use of hot is, you should go ask in the healer section their views, I bet you will find 90%+ all say that hot makes a great difference 1-55.
For Lichs and Savages
HoT for lich is priceless imo.
Got my HoT up to 172 on Lich so that i only take 27 dmg from the lich DoT.
Can stay in form for almost the entire duration of the spell w/o needing a heal
And never go oom,i have purchased every HoT,Hpfactor and Hp cm i can find. -jroc
My Savage has all HoT including lycan regen which adds up to a green 60 tick and puts my natural HoT at over 200. I love having all of it and it adds to my ticking mca which heals 310 for 8 ticks now. And it does also add to every tick from a healer; my wife's cleric Faithful at 600 charisma ticks me for 1129 if I remember correctly. For a Savage I'd recommend buying every HoT cm you can get.
Items with HoT
Yes and no. There is no limit to HoT masteries. There is a limit on wearable HoT. When figuring out HoT from items it goes like this.
1. Highest HoT numbered item - Full HoT
2. Next Highest HoT numbered item - half the rated HoT
3. Any other HoT item - get 1 HoT per item.
So if you had 4 items with HoT and they had 15/20/10/5 on them, your total HoT from those items would be 20+8+1+1 = 30. Even though they had a HoT rating of 50. This might not be exactly how it works, but it is very close to this. HoT items do not stack, HoT masteries do stack.
Basically for uber HoT you want good HP base, CM, and 1 really nice HOT item. I was skeptical of HoT and just bought it to play around, makes a big big difference in PoD , has often made the difference between DGing and just going afk for 3 min. Also helps nicely against casters, any extra HPs against a heavy nuker when solo could mean getting the kill vs. dging.