What should take only one day, often requires many more days. Not so much the loss of money is the problem, as the loss of valuable time.
In our experience, this happens all too often. Simple tasks are quickly done (and a tip received for good measure), only to show failure soon thereafter. We have lost count of the number of times someone replaced a water pipe (for heaters, toilets, faucets), only to have the replacement starting to leak almost immediately (and a new visit, and probably a new tip made necessary).