Traditionally there are busier and quieter times of the year for house selling. These are based on what much of the population is doing. December is quieter as everyone builds up to Christmas but the market tends to pick up in the new year - equally August tends to be quiet. However in these more uncertain times, I personally recommend that you don't wait, as despite what you endlessly read, the truth is nobody has any idea what is actually going to happen in the market. If now is the right time in your life to sell, get on with it asap. If the market falls lower by the ‘suitable time economically' you will kick yourself. Equally, if now is a good time in your life to sell, sell now, as you never know, the market may have moved down if you wait.
