你的理解很到位used to do表示过去常常做，而现在不这么做，如果不排除现在还这么做 可以用would dowould do 表过去习惯性的动作，翻译成：（过去）总是会。
。。如：The old man would sit in front of the house, waiting for his son to come to visit him.那位老人（过去）总是坐在屋前，等儿子来看他。used to do 强调过去曾经做过，而现在不做了，如：There used to be a hospital here, but now there is a beautiful garden instead.此地过去曾有一家医院，但现在却是被一座漂亮的花园所代替。