I would say you take more care with the sp less that that you are making sure that you take less care with the non-sps, if you know what I mean? If you arrive unkempt, unshowered, less than at your best, then you will not seem as appealing for a long term relationship lol.
With an sp, you know that the opposite will improve your mileage, so it is in best interest to be fresher. With a non-sp, it is not in your best interest to look like a great catch. A fun friend with benefits yes, but not a great catch.
I think you already know that even "booty" calls come with strings if you want to make sure you stay on their list. With an sp, all you need to do is show up on time and with a good attitude, you call at 9pm, arrive 9:30, leave at 10:30 and she actually does not want you to call her in the morning. It is the ultimate nsa.