know one's stuff(быть компетентным специалистом: If someone knows his/her stuff, it means the person is very knowledgeable and skilled in that area – This carpenter really knows his stuff because he has 30 years of experience. Bullfinch)
have been around the block(These guys are just top quality people and players, and then you look and see all the experienced guys who have been around the block.4uzhoj)