Yaşlı Vs. Eski

In Turkish we have two words that mean "old" and they are;

• eski
• yaşlı

How we know when to use the right one?

For living things we need to say "yaşlı".

*"Yaş" means "age". And yaşlı means "having age". -lı is a suffix add the meaning of "to have, with"

for example:
Balkonlu bir ev aldım. I bought a house with/that has a balcony
İki çocuklu bir aile. A family with two children.

*Eski means old, depreciated, worn out in Turkish. So we should use it to describe only non-living things.
If you look up a dictionary to learn how to say "old" in Turkish as an English speaker, "eski" will be the first word to see. But as you may agree, it is not nice to call someone "eski". It could be accepted for the plants only.

*You could call someone eski in only ths case;

oldschool - eskikafa

kafa and baş both mean "head" in Turkish. So if someone is oldschool enough then you are free to call him/her eski but with kafa together. Otherwise please don't forget my words to keep being polite when you speak Turkish. Thanks! :)