I'm new to this group, and was diagnosed with COPD (chronic bronchitis) right after a quad-bypass surgery in November 2014. On O2 therapy 24/7 since January 2016. No tanks, just using an Inogen O2 concentrator. Also got the special backpack so I can garden and do other things a 25-foot cannula will not permit. In the house I use the larger Respironics O2 concentrator with a 25 foot cannula, which gives me access to most of the house. While gardening or doing other physical chores, I need to set the concentrator to 5 lpm, and 3 lpm if just walking the dogs. I keep the Respironics unit set at 3 lpm, which lets me prepare meals (I am the cook and laundress since my wife went back to college to get a masters 28 years ago) and other normal activities. The 25 foot cannula gives me access to my den, studio (I am an artist), the master bedroom, dining room, kitchen, laundry, guest bath, and TV room. Most of the time, I forget about the O2 and my 25 foot tether, and joke about it to friends by telling them, "some choose to wear charm bracelets and I wear an O2 concentrator." We all accessorize to our own tastes. All in all, I always take my medical adventures with optimism, and ALWAYS follow the various doctors' orders. If I were pushed off the Empire State Building and around the 22nd floor you asked me how I was doing, I would answer, "Okay so far."