Just a quick side note worth posting. Detectors, both smoke and CO2, can have their life span cut in half if the people in the home they are in are smokers.
My brother runs an alarm company that sells and installs both types and they also will install the battery operated ones when asked. In homes with smokers his install crews see it all the time where the units are clogged from the nicotine and also the detectors closest to the kitchens can get funky from cooking greases from frying foods.
I love freddy's idea to buy a new one or two every 2 years and mark them with a date.
I am a bug about new batteries and replacing them when I switch the clocks back and forth for daylight savings. We are smokers so I checked my detectors this year and sure enough, the one nearest the kitchen was nasty and the one just off the living room was not much better. Rather then take a chance I replaced both and added a new CO2 one.
I do not have a draft issue with my stove but there are days when it seems the O/S preasure is heavy and my stove wants to just chug along and never really gets up to normal operating temps. These are the days when I worry and I always know when they are here because my neighbor burns wood in an old smoke dragon and I can see it hanging right above his roof.
Now for the good news, The last time I had to refire my stove from a lost fire was Nov. 15th, 60 days tomorrow without loosing a fire!