Which microscope head to buy? How many eyepieces?

Advantages of monocular, binocular and trinocular microscope heads. They differ in price and on comfort of use and photography. Monocular heads are the cheapest, small, light and do not have mechanical parts that might break. Binocular heads are good for long-term viewing and allow for the adjustment of eye distance and difference in eye-sight between the eyes. Trinocular heads can carry heavy cameras and allow you to take pictures while viewing.