Your footwear is the link between you and the ground.
Buy the best you can afford from a reputable outdoor shop. The comfort of your boots is vital, reducing fatigue and giving support on rough ground. Fashion boots aren't suitable and trainers are only suitable for easy terrain on good days. The lightweight specialist fell-runners wear dedicated shoes with deep studded off road tread, not road running shoes for this reason.
Winter requires additional support, with '4 season' boots capable of taking crampons and also with a more rigid sole, allowing the 'edge' to be used for grip on steep or snow covered ground.