I have never used full scripts for more than 5 minutes. I find them too busy, strange colors and bloated with all kinds of stuff I wouldn't even know what their use is.

So, I started with a clean mIRC and each time I needed something, I either scripted it myself so I could have it as I wanted, or I searched for snippets by others that do that specific thing and use and adapt them to my liking.

The main advantages for me are that my mIRC does mostly what I want it to do (unless I'm lazy) and I don't spam banners and quit messages in full color all over the place. Ofcourse I'm also fairly sure there are no (deliberate) exploits in my code.