When is an exception not an exception?

the Guardian -

the Guardian—If ‘just this once’ happens every month, there’s a name for it: a monthly expense One of the more infuriating challenges of personal money management goes as follows. Suppose your dishwasher breaks down. It makes sense to replace it with a good one, instead of something cheap that will need replacing again next year, so you buy a high‑end model, congratulating yourself on your wisdom. The following month, it’s your 10th wedding anniversary. You’re not the type to splurge on champagne-fuelled...

except for the house prices. When the McCartney family moved to 20 Forthlin Avenue, it sat in a neat council estate in a respectable suburb.