<prompt> Human: I would like some insight into calculating the method by which I should assess the quantity of dress shirts I can buy. Theyre for a sales finance job. I rarely find shirts I like at this store, and they are perfect. Heres the challenge: They only come in one colour, and are now 12 price. I own two, but Id like a couple more as reserve in order to have a supply when these wear out. I am not familiar with a substitute product that is equivalent or greater for the price quality value.In the past, shirts from this store last me 2-3 years. I wouldnt mind having a 10 year supply. Does that mean I should buy 10? 2? 5? 8?Im trying to learn how to put money away, and am having difficulty identifying my opportunity cost with this particular purchase. I would be spending 90 per two shirts. I have earned 26 900 this year so far, and am projecting earnings of 48 000 - 52 000 gross income.My monthly expenses are 1714 per month which nets me 14 432 in savable income at a over-projected tax rate of 30. That rate is intentionally high as I have not yet completed a calendar year at this position. I want to pay down my house, pay off my personal loans, and pay off my future education. How would you approach this situation, and why? I hope this wasnt in the wrong thread. Im unsure if I should be posting to reconomics, rfrugal, or something related to retail. Thanks!  <response>: They only come in one colourAre you a cartoon character? If not, please dont buy 5 identical shirts and wear them to work everyday. People will get the wrong idea. 