I price by time, you get used to how long things take you
I have various types of commercial, blocks flats, nursing homes and all the other add ons which is all subbed out, i often just give a day rate, you kinda get to know how long your subbies take, and if I'm unsure on some bigger stuff day rate seems to work out quite well, for me and the client it's very transparent if it takes less they pay less, I'm normally sometime say out either way
it's true there's a lot charging very small prices now but sometime they last sometimes you get a call a year later