I think it is important to change socks, underwear and undershirts every day since they accumulate organic material that will smell badly if it becomes moist. It is an experimental fact that the sense of smell is a differential sensor, i.e. you only smell the change in odors, not the odors themselves. The change from a more smelly place to a less smelly place is more subtle than coming from fresh air into a smelly place. Furthermore, humans grow accustomed to smells they encounter frequently, which is very bad in a laboratory situation like I had before. You cannot detect that your own home has a smell, unless you been away on vacation for more than a month. When you do come home, it will smell "like home" and you may not recognize that it stinks.
Beeing an Aspie, you do not necessarily detect that anyone is fraying their eyebrows or wrinkling their nose. Most people avoid comments related to smells, as it would be rude. Therefore, you will likely never get a verbal comment even if you stink badly. Take for example homeless people or severe alcoholists; noone ever comments verbally on their smell!
Having said that, I do wear the same pants several days in a row, never more than 5 days. I have found that owning several identical, or different colors of the same piece of clothing helps.
The following item has not been tested and may not work. I would expect that if you use different deodorant on two consequtive days, you might be able to apply the "smell test" to upper torso clothing. This assumes that you shower before going to bed.