You really need to own them, it usually takes multiple stretches before they'll stay.

And don't forget to thoroughly soak the boots in water before using the stretchers YES I SAID TO THOROUGHLY SOAK THE BOOTS IN WATER BEFORE USING THE STRETCHERS!! Then leave stretchers in overnite or longer, then stuff the boots with newspaper and let then dry at room temperature for 2-3 days. No heat guns, hair dryers, or fireplace racks! Yes it is a time consuming PITA but when you're done you will have as permanent a fit alteration as possible and virtually no "creep" backwards to the formerly tight, unwanted size.

I heard of the process about 30 years ago from a 68-year old man who ordered a pair of Donner heavy duty hiking/light climbing boots for a Dall sheep hunt in British Columbia. His itinerary was compressed due to guide availability and he called Donner to get their best accelerated breaking in process for new boots. They stressed soaking, wearing up and down stairs, and and keeping laces normally tight per usual.

He was one of my all-time heroes; booked a 9 day trip on the upper Priest River in BC, pack trip in and out with rubber rafts used in a couple of river crossings. With a day or two left on the trip he took a trophy Dall ram with an original pre-64 M70 .300 Winchester Magnum.

Can't remember his name but he looked exactly like the guy Charles Daly used in their ads in the late 1960s-early 1970s" rugged jawline, grey hair in a Michael Douglas type crew cut, nice tan, well dressed. Jack O'Connor had nothing on this guy!