I have been playing piano for more than 20 years. A few months ago I realized I started to play octaves with my 1st and 4th finger. I do not do it on purpose. i do it without even noticing it! I have very big hands as well. I can reach from a C to an F sharp ( 18 half steps!) Will this affect my hands/ playing in any way? Is this a bad habit? Am I most likely to make mistakes while playing octaves? if this is a bad habit, how can i change it? I dont know how long I have been playing like this, but I noticed this a few months ago.