Can you clarify a bit what you mean? Like how advanced pieces you can read fluently?
Yes, or the various "levels" you attain when new things open up. For instance, with technique, you can initially start off with basic chords in the left hand and melody in the right hand. Eventually, you gain enough independence to where you can play a Bach invention (and eventually, fugues etc.). You gain enough proprioception to be able to play waltzes fluently. At a certain level, playing the notes becomes fairly easy, and the difficulty lies in evenness and similar issues. And then interpretation, and secure memory. There's always a sort of pyramid of skills. I'm curious how it is with sight reading.