Nuff said- I don’t know how long I should keep mine usually.
I’m not sure I understand what you’re asking, but I use my container of deodorant till it’s empty, whether it’s solid, gel, liquid, or spray.
By stick, do you mean the solid form of the product, or do you rub a twig in your armpit? I shouldn’t be this perplexed this early in the morning.
I use it until it’s gone… then I buy a new one…
Was I supposed to be doing something else? 
How long does that usually take?
Wierd question, I know, but I usually throw mine out before then b/c I figure it might be, dunno, less fresh?..
Eh. Your deodorant is most likely stable for at least the time that it takes you to use it all up and chuck it. Apparently antipersperants have an expiration date on them, so go by that if you use antipersperant. Otherwise unless it’s taking you more than two years to go through a stick of deodorant you are wasting resources every time you throw out a partially used one.
Hrm… probably lasts a couple of months, maybe two or three - depending on the brand, type, etc. My Dove one is a solid and it’s lasted about a month now, still seems fine. I’m not so sure about that “armpits to underarms” deal they’re trying to get me to buy into, though. :dubious:
I’m not sure if it can be “less fresh”. Kind of like soap, you know? You’re just wiping a layer of it onto your skin. I suppose if it melted or something. Or, no wait, once I found one of my husband’s little sample sticks he likes to use for when we travel, and it had been put away for about a year - when I took the cap off it kind of crumbled. I suppose about a year of non-use is “less fresh”. 
A week or so after I am scrapping the plastic against my underarm, and I get around to buying another.
Perhaps what you are detecting is the aroma has somewhat diffused, much like a old air freshener and you are expecting that ‘new- full strength’ aroma.
When I grow tired of the taste and want a new flavor.
Meep! 
I usually like to switch off between different scents/brands/varieties on alternate days because (anecdotally, at least) deodorant seems more effective if you don’t use the same sort all the time. But if I don’t, it’s usually about a month per stick.
Iunno. Once every 2 months, usually. Although once I left a stick of deoderant in my parent’s car and it melted all over the inside of the cap. I couldn’t use it after that.
Every 2 or 3 weeks maybe?
They used to last a lot longer though. It seemed that they’d last 2 or 3 months back when I was in high school.
I thought this was going to be about the UL that your body gets immune to your deodorant:
http://ask.yahoo.com/20051118.html
(Ask Yahoo deems it false)
How often? Have never owned.
Do you mean how often do you change your current deodrant stick or how often do you change brands/scents?
For the former, when the current one runs out.
For the latter, when the supermarket’s out of stock (or discontinued) the current one I use. Usually when this happens I’m tempted to go with a difference scent as well.
I use Mitchum’s roll-on stuff, in the skinny green tube. Nothing’s worked as well as that*, so unless I hear of something better, I most likely won’t.
*-Except for one friend’s Lady Speed Stick gel. Go figure.
I’m about in the same boat. Deodorant lasts me a wickedly long time. I’d bet I use the same (unscented) solid for at least 3 months. I use it faithfully every day but I’d guess that I give it about 4 swirls around my armpits and set it down. I only realize that it’s out when I start feeling the plastic scraping my pits. It lasts forever!
The reason that I only use unscented is that I found long ago that certain ‘sport’ scents made me smell like a rabid weasel…I’d never really noticed it until I special someone asked me if I’d been hunting and using animal attracting scents earlier.
After ridding my nose of the odor…I sniffed the shirt that I’d worn. Godawful…I’m still amazed that I have friends…and still a few that talk to me.
I guess I’d estimate it takes me about 2 months to go through a stick of deoderant. I tend to apply it pretty heavily though, to be on the safe side!
I just wanted to say that deodorant CAN get less-than-fresh, and boy, is that a gross experience. I have a vivid memory of younger me finding a several years old deodorant sample and using it. Only after I had smeared the gunk into my pit did I realize that it was yellow and had the approximate smell and texture of extra-chunky milk. Traumatic.