When in Buy Mode...

Um, third option: "it depends".

I use both, depending on what I´m about to do. When I build a whole new house, I mainly sort by room, except for lighting for example, that I sort by function. Also, for some of the harder to find objects, I only know one way to find them, either by going for the room or function route.

That´s one thing I have to praise Sims 4 for: there´s a search function. Really, really wish we had this in Sims 3.

I almost always use function. It's still a pain to find stuff (I'm looking at you, misc decor <.<)

I didn't think about people possibly using Both...I'm sorry. :(

99% of the time I utilize sort by function unless there is something specific that I can't find easily by that method. If the latter (namely Mrs. McMulty's Magic Water Pump - trying to sift through hundreds of CC is especially annoying) is the case, then I utilize sort by room and if I need to find something really quickly, then I use sort by EP, the little triangle to the sort by function item window.

I use both depending on what I'm trying to find.

The "sort by room" option is best for me, when I'm trying to find store content, so I tend to use it a lot! Otherwise, I have to wait for the pictures to load for way to long, particularly in misc decor.

Sort by function I use when I haven't made my mind up about which funishings to use.

I also use the category to search for objects that I know fall into a certain expansion pack or stuff pack.