why do we have expressions like 'free time' , 'free afternoon' , and so on. , but we can't have 'free evenings'? What is the rule behind this? I was also searching and I found out that although 'free' is an adjective and can come before 'noun', in this meaning it can come either after or before nouns. Here it means 'available', but What makes me confused most is that when we can use this adjective before and when we can use after 'noun'?
I wanted the evenings free for going out with friends.
I wanted the free evenings for going out with friends.