Change history and trend defaults on multiple templates?

[slydog]

Is there a way to change the default history=7 and default trend=365 settings across all items in several templates by modifying a configuration file or two?

And would this be effective across existing hosts that use those templates?

[kloczek]

Is there a way to change the default history=7 and default trend=365 settings across all items in several templates by modifying a configuration file or two?

And would this be effective across existing hosts that use those templates?

It is possible to change this (only) for all items.
Web frontend -> Administration -> General -> Housekeeping:
History -> check "Override item history period" and change "Data storage period (in days)" to 7 -> Save

On the same page is part which allows change global trends settings.

[slydog]

Thank you, kloczek!