Unless you are an assistant manager, your hours are very limited. Usually 12 to 20. Also, most stores have around only 7 people on staff total, including the managers. So it can be hard to find someone to take your shift last minute.And you can't call out sick unless someone takes your shift - if you can't find anyone, or unless you're in like, the emergency room, then you HAVE to come to work. One time one of my assistant managers was forced to come to work with a debilitating migraine because none of the other three managers would/could take her shift, and I had to go to work with one of the worst flus I've ever had.
The only other thing that I can think of is that it *can* get a bit catty at times. In order to get a sale, the moment someone walks through the door you have to 'stake your claim' on them, so to speak, by greeting them, and then as soon as you see them with two or more items in their hand, (and you have to keep an eye out), offer to get them a fitting room. Otherwise, another associate might get them a fitting room or help them get something off of the mannequin or answer a question they had, and can "steal" your sale. In that scenario, the best thing to do is, once the associate is alone, politely thank them for helping your customer. That kind of nicely says "Back up, chick, I had that customer first". But after that you need to stick EXTRA close to your customer (with out being over bearing or annoying or clingy). Because at some point, if the other associate really is helping that customer more than you, then they really do have a right to that sale at that point, regardless of who greeted them first (and vice versa).
If you are caught up helping another customer, and so the other associate has to check your customer out at the register, try and work in a (genuinely) polite "Thank you, (associate name)" to reiterate that that customer is yours (so they can type in your number so that you get credit for the sale) or try to remember the customers name (you have to ask so you can put it on their fitting room door), so that, when the customer approaches the counter and you cannot check them out, so the other associate has to, then you can say "Hey, (customer name)! Did you find some cute stuff?" or "Did anything work, (customer name)?" or "I see you found some cute stuff, (customer name). Did those silver jeans fit well?" - which, again, subliminally says "I helped this customer". Please keep in mind that the majority of the time, none of your co workers are intentionally trying to steal your sale. They just might genuinely not know that you were helping them. And if nobody was helping the customer, then whoever checks them out has the right to the sale. We are just not allowed to ask "who was helping you?" to the customer.