The base spirit maximum of 150 is pretty low if you actually want to use those spirit-consuming skills frequently. It can happen easily that you don't have enough left when you're trying to use the more expensive skills for 50 or 75 spirit.
The only way to increase the maximum spirit I've found so far is the "Exalted Soul" passive skill, which increases it by 100.
Are there any other ways of increasing the maximum amount of spirit for a monk?
Best Answer
You're asking the wrong question here. Spirit is a fixed pool, the only way to increase the size of it is, as you mentioned, Exalted Soul. This is meant to be a bottleneck. The point isn't to be walking around with a full spirit pool to be drained, but rather to build up to using a Spirit based skill through the use of various generators. Thus, the solution, if you want to use more of them, is not to increase your maximum spirit, but rather, to increase the efficiency of your spirit generation and usage.
And for that, you have tons of options. First off, every Spirit Generator has a rune option to increase the Spirit it generates. Most abilities that cost Spirit have options to reduce their cost. Some, like Exploding Palm even have runes that make them near to self-sustaining under the right circumstances