I am considering finally breaking down and upgrading to 4.1

I was wondering if anyone had tips on making it smoother (I will be letting IPS do the upgrade for me)

I have for example old plugins that I don't think have new versions (Ticket Systems, FAQs, (HQ)Awards, etc) do I turn them off before the upgrade?

What about dealing with the skin which will break?

 

Looking for any guidance from those who have done it to try and make the transition as smooth as it can be recognizing some things will likely break.

I made several test upgrades on a test installation in advance. This way, one can clearly see what happens, which things break and you can test safely how to solve it. 

I also worked on the theme on the test installation. So once I made the upgrade on the live installation, I could just copy over my new 4.x theme. 

If IPS do the upgrade then they'll either instruct you to switch off all third-party items or do it themselves. Doesn't matter if there are 4.1 versions or not.

I also went to IPS for the upgrade and they provided great support throughout. Between that and what opentype said, you can't go wrong.