ABSENT MEMBERS
In practice, not all peers who are entitled to seats attend
the Lords regularly. Some are on official 'Leave of 
Absence' (for reasons of work, health, or foreign 
residence). Some have not received a Writ of Summons, 
entitling them to sit in the House (usually hereditary peers 
who have succeeded to a title and are either under 21 or 
have not applied for the Writ). And a few choose to give up 
the title for their own lifetime, either because they disapprove 
of the House of Lords on principle, or they wish to remain or 
become MPs in the Commons.