In Viking Clan, Stamina refills purchased with Favor Points will refill your Stamina reserves up to a maximum of 7,500.
The Stamina cap also has a sliding scale, where the higher you get in level and allocate Skill Points into Stamina the more you will get back upon purchase of a refill, up to the maximum of 7,500.
The sliding scale starts at 5,000 Stamina points.
For example if you are level 6,000 and have 7,500 Stamina, the max you will get back is 5,000 points. If your level increases to 6,900 and you still have 7,500 Stamina, you will receive 5,175 points on refills purchased with Favor Points.
An important note: The cap on Stamina refills also impacts the Stamina received from your Daily Rewards. For example, when you collect a Daily Reward of 60% Stamina, you will receive 60% of a refill rather than 60% of your maximum Stamina!