One of the good features we can use with SharePoint is the Retention Policy associated with Content Types and Documents types
Company ABC have a Library with a lot of photos of the employes, this folder was grounding bigger every day to manage this folder the Company define a Policy that each picture with more then 1 Months need to be deleted.
Microsoft SharePoint Out of the Box already bring a tool to manage this type of Policy, in this case, you need to go into "Pictures Library Settings" and "Information Management Policy Settings"
from there you need to select what content type you need to manage the Policy in this case "Picture"
When we select the option "Enable Retention" a new option will appear to manage the retention policy.
From here you can define the Events and Actions that will be associated to your policy,
In this case you need to define the "Time Period" to 1 Month and associate a Action, for this case i don't select "Move to Recycling Bin". Why? If you move pictures to Recycling bin and if you have Site Quota very low, that can have impacts and block you site when you reach the Site storage Limit, for this i choose "Permanently Delete". and is done... very easy and you can also create custom Workflow to create alerts for Reporting reason and also use the record management for repository... Retention Policy is very usefull very cool feature, you will like.... :)
If you want to create custom Retention Actions you can have this example from Microsoft
"Creating a Custom Expiration Formula Based on Metadata in SharePoint Server 2007"
and from "Yaroslav Pentsarskyy"
Hope you like :)