What type of clothing do you (or would you) usually run out of first, forcing you to do a wash (assuming that you do laundry as needed and therefore are usually compelled by shortage)?
If I get too lazy to wash my clothes when they start to really pile up, I will run out of pants first.
I try to have enough clothes to go two weeks without doing the laundry. If I’m short, I buy whatever ran out.
I put shirts. But to be more specific: I run out of shirts that I’m willing to wear.
I have a set schedule for the laundry, but when I don’t follow it I run out of underwear first.
Same thing here. I only have a few shirts that are ok for work and that fit me right, so once I’m out of those I need to do some laundry.
Pants, then socks.
It used to be my uniforms because I only had a limited supply of those.
I do laundry about once a week, so it’s never an issue.
If I get too lazy to wash my clothes when they start to really pile up, I will run out of socks first.
Tis the only reason I’m doing laundry right now. Funny, I was thinking to myself that I wanted some new clothes earlier this week, but as I was segregating my laundry, I thought to myself several times, “Ooh, this is a cute shirt! I forgot about this one,” and then ended up with two full baskets. So maybe I don’t need new clothes, but perhaps new socks so that I can put off doing laundry even further. 
I do my laundry every Sunday (that’s house-cleaning day). However, if some unforseen circumstance prevents me from doing laundry, I will run out of brassieres first.
None of the above. I have three classes of laundry:[ul]
[li]Whites – undies and socks, mostly[/li][li]Lights – Permanent press shirts mostly[/li][li]Heavies – Towels, trousers, work shirts not included above, etc[/li][/ul]When I run out, or get to the last one or two, of a class, I wash the class. I’ve about a two week supply and the heavies is two loads so I wind up doing laundry on average about every five days, I guess.
The briefs and socks are equal. so most of the time I run out of both on the same day. If one or the other wears out, it gets replenished from an open package in the back of the drawer. Likewise for the towels/pants. If I go through a lot of towels for some reason, I shrug and wash the pants that need it along with the towels.
It depends on the season. In the winter, it’s socks. In the summer, it’s underwear.
I run out of underwear first. More specifically, I run out of bras.
While my boyfriend will tell you I have no shortage of clothes in my closet, I will tend to run out of pants first. Let me amend that - pants that fit. I have about 40 pair of underpants (hee, I said underpants!), so running out of those would mean I’ve had some dire catastrophe in my life that allowed me the time to change my drawers, but not wash them. Also, if I run out of panties before doing laundry, I’d be naked anyway 'cause all my other clothes would be dirty. 
I never get to the point of running out of any clothing; I run out of towels first, then wash everything that needs it.
With me it’s not an if but a when. My socks run out first. I have been known to wear two pairs of socks over three days, for example. I’m only 20 though! I’m excused!
I have a washer and dryer in the bathroom so I do it every other day. I never run out of anything. If you can’t do laundry when you want but a few bags of socks and underwear and you should be all set. Same thing for towels, get a dozen and anything else you use daily.
I do laundry once a week, to keep my dress clothes for work clean. I usually don’t run out of anything (other than clean dress shirts) if I do laundry every Sunday or Wednesday.
Undies. If I run out of panties, then I do laundry, unless provoked by TheElf’s shortage of shorts, then I’ll do a load just for him and continue to put off laundry until I need something.