Both the US and Japan have extremely varied costs of living depending upon where you’re talking about. I live in the countryside and things are generally fairly cheap, though inflation has been hitting hard since corona and a poor rice harvest last year. I studied the language a bit before I moved, came over as a language student (probably second-oldest there in my 30s), and found a job a few months later. I’m conversational, but my reading is pretty crap. I generally do all my own medical stuff and the like, though definitely run documents by my wife to make sure of some things (particularly government and finance). We basically only speak Japanese at home.

Tokyo can be expensive or not totally depending upon the experience you want to have. No need to own a car so no inspection, tax, insurance, gas, and parking spot cost. I lived there for 8 years without driving at all but did end up getting a motorbike after moving to the suburbs. I had to get a car when we moved to the countryside. Houses are going to be much smaller and much closer than most of the US. I earn well above the median salary (which is something like 4-6 million JPY/year for someone in their 40s) and pay roughly 26% of that out to pension, taxes, etc. Healthcare is far cheaper than in the US but not free at point of service like other countries. There are out-of-pocket maximums over some periods and tax rebates on the year if you go over 100k yen.

Thanks!