I have several light swithes in a 35 year old house that are always on, if the switch is up or down. So to turn the light off you have to balance the switch in the middle! Is the switch bad or is it miswired? (I just moved into this house)

Thanks!

If they are single pole switches,(2 screws)It is bad switches.
If they are 3 way switches, The're is a way to miss wire to duplicate your problem.
Good Luck, If 3 ways write back for soultion. Longer answer