Board Thread:Suggestions forum/@comment-26172435-20160707105627/@comment-26172435-20160708161830

I've pondered methods to limit the max buff: either 1) linear equation with a fixed cap, or 2) some exponential equation that sets a fixed cap.

In case of 1) the vigour effect will increase linearly with the experience orb level en be capped at, for example, 50%, which will be achieved at 100 levels with an effect increase of 0,5% per level. The maximum of 100 levels seems a practical one to me. Only die-hard grinders, the bastards who'd practise the ways as described by Cirdan above, would achieve that, and it's still up to server staff to check whether folks are grinding or not. Any levelling system will have the potential of grinding abuse ... the key is to choose wisely in the design of the mechanisms of the system.

In case of 2) the effect increase per level will gradually decrease from some starting percentage (say 1.0 %) at level 1 to zero at level infinity, resulting in zero effect increase at tunable level of 100 or so.

I prefer the linear variant as this ensures the reward of levelling up and playing carefully doesn't fade out too soon. I included this in the OP, together with a recommendation to implement two configurable parameters: the effect increase per level and the level cap.