Candidates' reasons for moving positions are always varied and personal; however, when speaking to candidates about why they are interested in making a move, there is one reason that I hear raised time and time again: lack of mentorship.
A common mistake is confusing your mentor with your sponsor. While a mentor is a key part of your professional team who will provide advice, guidance and maybe even get you on a few files, they will not be the one petitioning the partnership when it comes to your annual review and advancement decisions. That is the role of a sponsor.
The fortification of personal bonds at work will ensure excellent junior associates develop a deeper sense of loyalty and commitment to the firm. Mentorship develops those bonds in a positive and professional manner.