Is it OK to use the same variant in multiple process chains?

I'm just getting started building process chains (in BW 3.0), and I'm finding that there are many cases where a process variant already exists for a process I want to perform (e.g., activating a particular ODS).

I'm curious if there are any risks associated with reusing a process variant in multiple chains? For instance, I've heard that if you modify and activate a process chain that is currently running, it kills the chain. Could the same happen if you activate a chain containing a process variant used by another chain that is currently running?

Also, would changes made to the shared variant apply to all the chains that share the variant, or does each chain get it's own local copy of that variant?

Thanks,

Bob