Unfortunately, it is very difficult to tell how long symptoms will last as the menopause is different for each woman.
Some women may have very few symptoms for a short period of time whereas others may have lots of symptoms over a number of years. However, symptoms can also be linked to your general health, diet and stress levels so looking after yourself well at this time is really important.
Caffeine sometimes triggers hot flushes, so keep caffeine intake (coffee, tea, fizzy drinks) to a minimum and ensure that you are drinking plenty of water to rehydrate yourself. Dehydration can cause feelings of anxiety, which then makes flushes worse.
It is worth checking if anything else seems to trigger the flushes - some women find that spicy foods or sugary foods will affect them. Also, if you are stressed then flushes tend to come along more frequently, as adrenalin affects circulation. Doing simple breathing exercises (e.g. counting to 3 on the in breath and another 3 on the out breath) several times a day can often help. If you feel a flush coming on, taking slow, deep breaths can stop it getting worse. Drink some water and give yourself a minute.
It is important to check with your doctor as they can be caused by other factors such as low iron, low thyroid or low vitamin D and your doctor can test for these.
In the meantime you may find sage helpful, this has been traditionally used to help with flushes and sweats.