Same as above. I think thats what the fellers did in the 50's.
My grandfather and I often have long discussions on care and maintenance of pipes (for those who don't already know the story, my wife and I care for him in his declining years). He hasn't smoked a pipe since the 70's, but, like all of us bretheren of the briar (or cob, clay, metal, or meer - if you smoke Brylon you're on your own!), he is opinionated, curmudgeonly, and loves to talk about all things tobacco.
He relays the following tale about pipe-ownership. In his youth (pre-War years), it was common practice for his mother to buy him a new pipe each year for his birthday. Upon receipt of the new smoker, the old one would often be round-filed (unless he received a real dog of a pipe). His pipes never saw a pipe-cleaner, nor a reamer; and would smolder from dawn to dusk, 365 days a year. When asked how he dealt with a sour pipe, he replies simply "You just did.".
The last pipe his mother gave him was a '65 Dunhill - he doesn't remember the line, but recalls that it was a simple straight billiard. Shortly after receiving the pipe, his mother passed away, and my grandfather made the decision that this Dunhill would be his "go-to" pipe for sentimental reasons. He figured it took him about three years to actually develop a burn-out - but he did. Seems the repair that his local B&M performed was quite clever - they drilled out the burn hole (right at the base of the bowl) slightly, then inserted a jewelers screw into the resulting tunnel.
***note: I don't treat my pipes like this - I fall into the clean 'em daily, and introduce alchohol and a reamer once per month category.
Sadly, I did not inherit any of his pipes; nor his brothers or fathers. To them; pipes were as disposable as a cigarette filter.
Oh, and to answer your question; before I was able to add to my rotation through the discovery of cobs, I found that I could smoke the same pipe up to three times per day without
too many detrimental effects. Of course, this also assumes that you are able to break down your pipe and give her a good cleaning after each smoke...but, of course, YMMV depending on your technique.
As stated by others, I would consider either a couple of Missouri Meerschaum cobs or a Dr. Grabow or two to extend your rotation some...you should be able to pick up the cobs for