Right now, if you specify that you want to keep the last 20 of builds, and you
also specify to keep the last 30 days worth of builds, Hudson will delete all
builds that are either older than 30 days or are not within the last 20 builds.

I would like to Hudson to not delete a build unless it is over 30 days old and
is not in the last 20 builds.

When a project is active, and I keep only the last 20 builds, I might only be
keeping two or three days worth of history. Therefore, I usually tell the
project to keep all builds younger than 30 days. This gives the developers
plenty of history in Hudson.

However, when that project goes into an inactive period where there are only one
or two commits per month, I suddenly go from keeping over 100 builds to only six
or seven builds because I am keeping only the last 30 days worth of builds. In
that case, I have to change Hudson to keep the last 20 builds.

Since projects keep going from active to inactive periods, I am always adjusting
the projects' configurations to go from keeping the last 20 builds to the last
30 days worth of builds. It would be nice if I didn't have to keep changing the
projects' configurations.