You should do what you can to avoid your Will being disputed after you die.

In our experience children like to be treated equally.  If you treat your children differently you should wherever possible tell them what you are doing and why.  If that is difficult for you, leave a note.  Try to avoid any critical tone and keep the message positive:

Eg “I am leaving your sister more because her financial needs are greater/ she has sacrificed her earnings to look after me” rather than “I am leaving you less than your sister because you have done less to care for me”