My housing and the healthcare services I pay for are the same as in 2008. I now have to pay twice as much in USD for the same goods and services.

That is the definition of currency inflation.

Exchanging more for the same.

That is an adjustment of relative prices, inflation is the generalized increase in nominal prices of all goods.

There is something called "asset inflation" but its not a correct terminology.

When housing and healthcare are >50% of my expenses, how much more general does the increase have to be to be counted as “inflation”?

It has to affect your salary too, which tends to be >50% of your income.