Reply to Can I use a 1N4007 instead?

Got a pack of 1N4001, then felt that they were kind of dodgy looking since half of them had the markings half off and the entire bunch was mixed with other values. Went to another shop and the lady insisted that 1N4007 was alright. I didn't argue since someone else was paying for it and it only costed a few bucks (in my currency). Can they be used or must it be 1N4001. Is the higher tolerance of the 1N4007 detrimental in this situation?