One thing I unexpectedly did very often was buy groceries in college. Most of the places I lived had kitchens which also meant I feld obligated to actually cook and, well, buy groceries.
In college, I was constantly busy and overwhelmed. I sometimes went to the grocery store with no list and left with hardly any real food. Other times I bought too much and ended up tossing expired fruits and snacks. But, by the end of the four years I established a pretty solid grocery shopping routine and even managed to do so on a pretty solid budget.
