Replace wheel bearings or clean and grease?

[Wypipo]

I have always been told to add grease to the wheel bearings of any bike when you buy it new. Now that I have the bike down I decided to go into the wheel bearings. Some say to spray them down with brake cleaner and repack the bearing. Some say the bearings are not meant to be clean and repacked they need to be replaced instead. I took the rubber seals off of both sides. One side exposed the bearings and the other has a retaining clip and another seal. If I clean do I take this side off and just spray brake clean through until it?s clean on both sides? I found the seal and bearing kits which aren?t very expensive. If I do replace them do I need to add grease to the brand new bearings? If so that requires me to open the seal which some say do not do, but others say you must add grease because there isn?t enough. Here is a picture of the inside of the bearing. There is some rust circled in yellow. But the balls of the bearings do not have rust and the bearing rotates fine.