When you have access to more than one NS account, which one, in your opinion/suggestion, is a better approach for maintaining the logins - all access on same email address or email address based on customer name?

One email is way easier. Having a bunch of customer-specific ones kind of sounds like a nightmare. I'm rarely ever actively working on more than 2-4 customers at a time typically, so I'd just hide any of the others off my list so it didn't get too cluttered.

But customer specific emails make it easier to assign the work to someone else. right? Just weighing the pros and cons.

Oh I thought you were talking just for yourself. Yeah customer-specific ones probably make more sense if you're delegating.