Field widths or formats

Designing a record for a database is a bit like designing a form on paper - you have to leave enough spaces for fitting in all the characters. Consider this section of  a form.

Is there enough room for your own personal details?

Would there be enough space for double barelled names like Webster-Simmonds?

What if you lived in a town called South Woodham Ferrers, would there be enough spaces for all the characters?

It is as important to leave sufficient space for data in a database record as it is on a paper form or words will be cut short.