As much as you want ! How many days and for which event or project you want to volunteer is up to you. Some prefer to contribute on a regular basis, others prefer to work on a temporary project. 

For some structural tasks, a volunteer fee is paid. If a compensation is applicable, it is indicated in the volunteer vacancy or communicated by the community manager. By law, you are allowed to work 52 days per year as a paid volunteer. Please note: this time limit applies to all volunteer organisations. If you also do paid voluntary work for another organisation than Herita, these days count towards the total.