A couple of people [ Steven Chan , Niall Litchfield ] have blogged over the past week about patching an Oracle EBS environment.
Steve says, "I'm compelled to make an admittedly-quixotic attempt to persuade you that the benefits of keeping your E-Business Suite environment up-to-date far outweigh the costs."
In general I agree with him based on my past experiences. A few times, due to a number of reasons, I haven't been able to do as much patching as I would have liked. That has come back and bitten us a few times by hitting issues that we wouldn't have encountered otherwise. There can be a substantial cost to troubleshoot issues. It usually requires time from DBA's, developers, QC and end users. That can add up pretty quickly.
For us tho there are three reasons why we are not as current as I would like. For large efforts, such as upgrades, its very difficult to put a dollar value on being reactive instead of proactive. There is also no guarantee that being upto date will reduce the number of issues or if they will resolve outstanding issues. That makes it difficult to make a case with upper management.
The other reason is because of testing requirements and/or testing resources. We have some custom modules and code so there is a fairly rigorous testing cycle for any change that goes into our environment. We have 2 teams dedicated for testing and at times we have to bring in end users. A testament to the testers tho is that we rarely encounter issues after changes go live.
Lastly, since business has a backlog of requests, our work often takes a back seat. Its a continuous fight to be able to put in some of the things we would like to do. I'm happy to say tho that we have done a bit of work over the past year to upgrade our hardware, consolidate environments and implement features such as Shared Application Filesystem and merging patches to reduce downtime. We recently put in multiple application tiers and without a shared filesystem maintenance would be a nightmare.
Currently we have some very aggressive projects going on at the moment. We are upgrading to 10gR2, implementing the Sales Compensation (OIC) and Projects modules. And if that wasn't enough, upgrading to 22.214.171.124. I think its safe to say that the next 6-8 months are going to be very busy.