Simply put, do not wantonly spend Primogems. It’s easy to spend your time-earned or cash-bought Primogems on a brand new character or shiny new weapon Banner. Resist this urge. Genshin Impact is a gorgeous, content-dense, free-to-play adventure, but keep in mind that Genshin Impact is a gacha game at heart. Mihoyo’s cash cow is the randomized character and weapon Banners where you gamble for items, with gamble being the operative word.
You could roll once on a Banner, and get extraordinarily lucky, but the odds are you won’t. You’re guaranteed a four-star weapon or character at 10 Wishes, and guaranteed a five-star weapon/character at 90 Wishes. Since you only earn about 60 Primogems per day, not including bonus gems during events, it can take between two and three days to earn enough Primogems to wish on a Banner. If you’re buying Primogems, then you’re spending about $2.60 per wish, $26 for a ten-pull, and $234 for 90 rolls to guarantee a 5-Star unit. With a new Character Event Banner circulating every three weeks or so, you are going to be spending astronomical amounts of cash trying to acquire every unit as they’re introduced.