automatic value removal after time & changeable date formats

Hello,
i got two enhancement ideas:

1. Add a option to enable automatic deletetion of values and a dropdown to select the timespan.
example: you only want to store two years of data. Activate this option and chose 2 years. Data older than the selection will be deleted.

2. Add an option to select different displayed date formats. Sending the date in the date('Y-m-d H:i:s') format is ok. But showing other formats in the visualisation and log lists would be great.