On believing one's customers

I have just spent 11 hours on what should have been a simple job for a Sunday afternoon, importing a customer's information into my database, because I believed what he told me. Silly me: I assumed that the data in his spreadsheet, which he uses every day, would match the description which he gave me.

Example: there are three fields marked "Height", "Width" and "Depth"; these stand directly beside each other, in such a way that one cannot possibly see one of them without also seeing the others. Yet in around a fifth of the records, the data was entered incorrectly: either all three values were in Height and the others remained empty, or Width and Depth were concatenated.

Example: several fields which were described as holding (only ever) numerical values, sometimes also hold a block of text explaining why this particular record is different.

Lessons learned (writing things down so that I will remember):

1) ignore the customer's description, look at what is actually there.

2) assume that every field will contain (at least once) a block of text in addition to what it should contain.

2a) always and only import data as text: if you put "0000746356" into a numerical field, it displays "746356". My bad, I should have anticipated that.

3) double the time you estimated for the job, and it'll come out about right.