No rules
When I choose clothes for any look, I follow only one rule: «No rules». Believe me it is possible to combine incongruous clothing if the whole look is harmonious. There are so many articles about how to wear leather leggings that you haven’t enough time to read everything. «Leather is the second denim», I think it is also already clear. But the claim that leather goods «should not touch each other» and «leather trousers must be worn with shoes with low-shafted with high heels» you can try to disprove.