Assuming the following:
- Operating arbitrary software in a completely read only environment is impractical. (While some software will operate RO without issue, it can be nigh impossible for other software, particularly if source code is not available as is sometimes the case)
- Rebuilding any machine in place is trivial and takes a negligible timespan with whatever method is being used, be it prebuilt images or via configuration management tools rebuilding them or any other combination or alternative.
- Destroying a host will not cause any downtime or service degradation.
Is there any reliable way to estimate how long an OS/Host should be allowed to 'live' before recycling it?
Ideally a way that avoids 'unnecessarily' excessive recycling which regardless of how efficient it is, will be adding overheads and performance penalties which would be best avoided as much as possible.