Joe,
Here are my 2 cents:
I used to do a ton of skull crushers back in my bodybuilding days... after a loooong absence (15+ years) and having resumed training 4 years ago, I have never needed to isolate training for the triceps; bear with me while I digress a bit to make a point on awesome dips are.
These are my press and bench press records, which are probably not a big deal, but bear in mind I'll be 40 in a couple of months:
bench press: 330#
press: 195#
Not superstar marks by any stretch of the imagination, but interesting nonetheless because of the fact that when I was in my 20s, my training revolved around maximizing the bench press (I used to compete), but back then, despite being much younger, my record was 20# lighter at 310#.
Before I used to train Bench every 5 days, and I did a massive amount of isolated tricep exercises, having skull crushers at its core.
Nowadays I will train bench once every other week, alternating with flies (solely for aesthetic purposes), inclined flies once a week, press once a week and do weighted ring dips once a week.
The irony is, I train much less than I did back when I was in my 20s, and although my training really revolves around squatting, I haven't stagnated. I think the fact that I'm training less has a lot to do with it (resting more), but I also think the dips have played an enormous role in this. Just food for thought