When should I use a TAE buffer for gel electrophoresis?

TAE (Tris-acetate-EDTA) buffer produces better separation of fragments larger than 2 kb and is a good choice for gel electrophoresis when working with larger DNA fragments. It also works better for DNA extraction from agarose gel. 

TAE is better for cloning because, unlike TBE, it doesn’t contain borate, which is an inhibitor for many enzymes.