Bitcoin is money, so spending really comes down to Gresham's law.

Specifically, about spending Bitcoin: Of substantial purchases, Land or Housing is probably the best use I can think of, in that it satisfies a higher hierarchy of need than money. Same for food, but I would suggest not spending BTC on food without replacing the spend. You will still regret the deflation in satoshi prices in years to come. But you continue to live another day.

I personally own almost nothing, and no land. Maybe one day. I own good computer(s). It’s worth buying quality hardware.

I’ve spent coins on vacations too, which is not advised, as these are ephemeral and bite harder when Satoshi prices change. Better to reward yourself vacations as proof of your work.