Question About Peak Flow Meters

(For those of you who don't know, a peak flow meter is a little device used by people with asthma and similiar conditions to monitor lung function.)

My question is do these peak flow meters need to be replaced periodically? I've had mine for about two years now and suddenly the little indicator seems to be sticking. I've tried cleaning the flow meter, but it didn't help and my lung function doesn't seem any different. What should I do now????

My sister buys a new one every year or so, for the same reason.

Her doctor said they should last 3-5 years, but I wouldn't use my toothbrush that long either so mine gets replaced every 6 months

I have had mine for several years now with no problems. / However, they should be replaced every few years when the tab (the little red one) starts to stick- because it will not give you an accurate reading of your lung capacity when it is sticking. So go ahead and get a prescription for a new one just to be on the safe side and make sure your readings are accurate

My older sister has had hers for 3 years now. She lost her old one that she had for 10 years and thats the only reason she got a new one.

Thanks for your help guys!