Out of sight, out of mind. We tend to forget people or things that we do not see
Opportunity seldom knocks twice. Don’t miss opportunities that come along
One swallow doesn’t make a summer. A single satisfactory event does not mean that all the others will be as good
One man’s meat is another man’s poison. People don’t always like the same things
One of these days is none of these days. ‘One of these days’ remains vague