You know how whenever you unpack anything that needs assembly, it always tells you to check you have all the parts before you start? Well here's a good example of why it's so true!

I had a nice little "Friday afternoon job", fitting a cat flap for a lady just round the corner. Eager to get home for the first beer of the evening, I was about to cut a great big hole in her back door, when I thought I'd better just check the instructions. Instruction 1: check all the bits are in the box. OK, there are only about six parts, plus a handful of screws. Shouldn't take long... except there's one piece missing!

If I'd cut the hole, she'd have been left with a 10" hole in her back door all weekend, which even in good weather isn't ideal. As it is, I can reschedule the job for next week, once she's got a replacement cat flap with all the bits.

Better safe than sorry!