Office Etiquette

So, I work in a cubicle.  And there are other cubicles, of course, in the office.  I can hear whatever it is the other people are doing: typing, talking, tapping their fingers.  And of course, I can hear whenever someone sneezes.

Given that it is allergy season, it seems that every time you blink, someone is sneezing.  I am of course exaggerating, but not by much. At first, I was saying "bless you" every time someone sneezed.  Other people were also saying it too.  Then I noticed that as time went by, the "bless yous" were less.  It was like only the first person had to say it, and it was kind of like bless you chicken to see if you say it, or someone else does.

But I did notice that some people didn't say "bless you" when other people sneezed.  So, I started to only say "bless you" to people that said it back.  But after awhile all the "bless yous" ceased.  Now occasionally there is a "bless you," but much less often than there are sneezes.  And every time someone sneezes in the office I feel this weird awkwardness, do I say it, do I not.  And when someone randomly says "bless you" to me, I feel weird, like I should have said it last time, but ignored it.

That got me wondering.  What is the proper etiquette for saying "bless you" in the office (especially given that it's allergy season and it's sneeze-a-palooza everyday)?  I know that it's polite to say "bless you" to sneezes, but honestly I just don't have the time or the care to do it every time.  I think that someone needs to come up with a count, or something.  You only have to say it so many times a day, or once a day to each person.  Or we could all just agree to not say it, unless by habit.