It's best to ask your doctor for his or her guidelines. The type of implant (cement or cementless) makes a difference. Your age and weight, the condition of your bones, and your general health may factor in, too.
A recent survey showed that doctors don't all use the same timeframe for activity restriction. An average of recommended time for each activity you mentioned would be as follows:
lifting 10 pounds: okay after seven weeks for cemented hip implants and eight week for cementless hip implants
climbing a ladder (step stool): okay after 12 weeks sitting in an office chair: okay after six weeks.
Other guidelines included driving a car (five weeks), working on hands and knees (11 weeks), and use of a regular-height toilet (six to eight weeks). Most patients add new activities gradually after six weeks as they feel able and safe.