Been on remeron (mirtazapine) 45mg at night for sleep and depression for about 2 years how hard will it be to change I sleep to long and take to long to fall asleep?

Talk with doctor. From what a psychiatrist once taught me, once you get over 15mg, the Remeron (mirtazapine) does not have much of a sedating effect anymore, so may not be helping you get to sleep. Do not stop it if you are taking it for depression. Speak to your doctor about other options.