@hattie43 It really does depend on what you’re doing on your trip. We spent approximately £50 per person per day on our last trip for two people in our late 30s.
We don’t drink much alcohol though. We were mostly eating 2 meals per day out (some of or hotels included breakfast) generally in small mom-and-pop places or in Japanese chain restaurants with the odd alcoholic drink here and there. Ramen bars, okonomiyaki places, little cafes, curry places, that sort of thing. Then some meals were street food, fast food (e.g. yoshinoya or mos burger) or convenience store buys.
We didn’t buy expensive souvenirs. We bought some baseball and sumo merchandise, I bought a few items of clothing in Uniqlo and muji, some makeup items for family and then the rest of the souvenirs were things like snacks, bath salts, stationery and other small consumable things.
I’m sure it’s possible to spend a lot more, but it’s also certainly possible to spend less. We frittered money on silly things like gacha machines, bought the most expensive tickets for the baseball game that we went to, upgraded some of our trains to the premium car etc. However, if you wanted to eat in high-end restaurants, drink in fancy cocktail bars and buy designer items or expensive gadgets and anime figurines as your souvenirs then I’m sure you could spend three times that quite easily. Theme parks can also push up costs.
Your Visa card should be fine, both mine were. I always like to make sure we have a few cards between us just in case though.