Is there a way to visualize border edges of meshes? When editing a mesh, it sometimes happens that two faces are seemingly connected by an edge, but these are actually two edges on top of each other. Often enough I only notice this way later. For example when moving one of the faces, revealing the hole in the mesh.

In Maya there was an option to highlight border edges. Does Blender has something similar?

Or this there another workflow in Blender to detect gaps?
Did you mean check non-manifold? 

Type select non manifold in search-bar (F3 or Space) in verts select mode(edit mode) when selecting nothing.

It will help you to select something not manifold including separated holes