1-10? I'd say a 0; the only redstone that I use is powered rails placed on top of redstone blocks, and if you want to count them doors and buttons (both categorized under "redstone" in the Creative menu), and a dispenser to store maps (the 3x3 inventory goes nicely with a 3x3 map wall) and trapped chests for more compact storage (both used for storage only with no other redstone).
Well, maybe not that bad; I do know how many of the components work but I don't see much use for redstone with my playstyle (I imagine that the main use of redstone in singleplayer Survival is automated farms, which are of little use for resources that I get from caving, and farms like a crop farm aren't of much benefit when it only takes a minute to harvest and replant enough food for 24 hours worth of playtime, and I spend almost no time near my bases so they can't really be automatic).
I'd say four. Maybe five if I'm being optimistic. I know how all the various functions work, and a lot of the shortcuts. However, when I try to put everything I know into practice, it has a strong tendency to simply not work how I want it to. There is some intuition or experimental process that I am missing that would allow me to create my own working redstone designs.
Probably a 4-5. Can generally figure how to do something, but still have a bit of trouble remembering recipes and getting complicated timing right. Have issues sometimes with comparators not acting as I think they would.
I always like to learn new tricks but I don't use redstone very much partially because my creations are always about five times bigger and more sprawling than they need to be. Lately I've been playing with comparators, they're quite fun when you learn to use them.