There's one thing I do tend to play around with, and that is my base/primer for pre liner eyelids, if I have a long day ahead I like to give my liner as much staying power as possible. I've tried a few different products including the Urban Decay Primer Potion, but so far I've found nothing works quite like the Bobbi Brown Creamy Concealer in Sand. This stuff is the furthest from creamy when used on my skin, but for blemishes and using as a base it actually works very well and keeps everything in place for a little bit longer.
For my everyday eyeliner I will never be without the Collection Fast Stroke Liquid Liner in the stash. Cheap and cheerful, with a good matte finish and decent lasting power - why would you stray? Everyone applies their liner differently, but I like to start with the middle and work out to the end of the flick, and then back in. It's never perfect but I'll be dammed if i'm going to wake up 15 minutes earlier each day in order to get it just right - ceebs.
You can give me a new mascara any day but I'll still always come back to Maxfacor whether I use the Masterpiece Macara or False Lash Effect ... or the waterproof counter part of FLE you see above, I just lurveeee full thick lashes.
My 15 year old self and her scene kid cat eyeliner may be well and truly in the past, but I have a feeling my love for liquid liner will always live on - have you ever seen a 90 year old woman wearing eyeliner? Might be worth checking back here in 70 years time...