Hiero
Regular
It depends on what you are at right now. If you are between 1:00-1:30, then I suspect you will probably get down to around 40 seconds in about 2 months. Once you learn 4LLL most people I know average about 50 and work their way down to 40 seconds within a few weeks. If you are naturally really good on the cube you might get down to 30 sec.averages. I think it takes some time and focused practice to knock off time when you are averaging in the 20's. Just my opinion and experience I have with other cubers.