Old people in dreams tend to suggest traditional thought or wisdom arising from experience. We may also need to consider our attitude to death. Old buildings can signify a past way of life, which we thought we had left behind.
Antiques will often represent elements of our past experience, which might be worth keeping.
If something seems particularly ancient, the meaning may be ambiguous; either it has outlived its usefulness or has been imbued with special significance because of its antiquity.