Used a couple of US recipes recently and most of the ingredients are in cups, or spoons, not by weight. This is a nightmare to convert. Do Americans not own scales or something? What's the reason for measuring everything by volume?
It really depends what sort of recipes you're making, but for cooking very loose approximations are often fine.
I often have to convert to weight/mass in order to find out how much of an ingredient to buy. I have no idea how many cups an eggplant is. But once I get it home the recipe might as well say "however much eggplant you have."
If I'm truly off, I will typically scale up the recipe adjusting for the extra meat or vegetable content. I'll more or less assume that 1lb of meat is interchangeable with 1lb of veggies. That's not quite true, in particular with salt.
Your mileage may vary though. Some recipes and ingredients are much more sensitive to deviations.
I'm going to estimate 99% of recipes in the US don't give weights for those. It will say one large onion or 3 medium zucchini. There are a few places (serious eats) that tend to give weights but it's extremely rare. If you're lucky you'll get volumes but weights are so rare.