You can get data on how much people are spending in retirement, but if a couple with a paid-off house is spending only $30K per year, is it because they cannot afford to spend more or because their needs are minimal?
It would be interesting to see a survey of retirement spending alongside questions measuring financial distress. You could ask people or collect data on whether they (1) face eviction due to late rent or mortgage (2) have difficulty paying other bills (3) worry about money a lot (4) avoid taking medicine because of cost (5) forgo vacations or other leisure activities because of cost
Of course (5) is a lesser problem than (1-4).
Is there data on how happiness or welfare in retirement income depends on spending power?