Can most patches be applied while all processes live?

I had a general question about applying patches to the system via adpatch.

Typically I've always just shut everything but the database down, applied the patch, performed post install steps, and brought everything back online.

I read through a lot of patch readmes, and noticed in a few they specificly state "make sure the tcf server is down", or "make sure the forms server is down".

If nothing is explicitly stated in the patch documentation, is it safe to say I can apply it while the system is live, the possibly just have to bounce it after post install steps?

I ask because I just go a huge list of patches which need to be applied, and don't want to make the system unavailable to developers during this whole time.

Thanks

I too, prefer that everybody is out when I apply patches. However, I think that the c*.drv files can be applied while everybody is in, but since the d*.drv goes against the database I would think that everybody has to be out. The g*drv files re-generate reports, so they should be out then as well...

However, I'm pretty new at this part, so I'm probably not a good source...