is the burn down chart required to measure the time in sprints or is it ok to have the time in days as wel?
Product burndown is usually tracked in sprints (e.g. story points completed per sprint).
Sprint burndown is normally tracked in days (e.g. task hours completed per day).
Burndown is not required at all. It is just a tool to visualize progress in the sprint. The team can choose whatever method they want as long as they inspect the progress toward the sprint goal. Personally I prefer the sprint burndown to show completed stories or story points and not tasks, since we're delivering stories and not tasks.
If you're talking about release burndown I don't see the difference between days and sprints. All sprints have the same length and the next sprint starts as soon as the previous ends, but maybe I got the question wrong.
While the Sprint Burndown is no longer required per se, monitoring sprint progress in some fashion is still required, and it is still required to sum the amount of work remaining in the sprint on a daily basis.
Most teams use a sprint burndown for this purpose, and while you don't have to use a sprint burndown, you do *have to use something.*
What units you use is flexible. Some teams use ideal hours, real hours, ideal days, story points, the "number of tasks", number of acceptance tests, etc. IME, most teams use something like ideal hours or ideal days, with the more advanced ones doing "micro-stories" and burning down in story points.
More about micro stories here:
it makes sence like you wrote Ian that there is a product burndown tracked in sprints and a sprint burndown tracked in days.
I read somewhere that the burndown should be tracked in sprints and i thought that they meant this was regarding the sprint burndown, however i think it was meant like you explained Ian.
Thanks the replies!