Always follow up with business connections within 24 hours of their business card being placed in your hand!
Follow up via email or phone call while the memory of you is still fresh in their mind. Between work and personal life the longer you wait to follow up with them, the harder it will be for them to remember who you are and what your business was.
It will also make you look efficient and on top of your game if you connect with potential business connections as soon as possible. Who doesn’t want to work with someone who gets things done?