Related Clues:

• Ready for service, nuns gam­bolled every now and then
• Worth keeping around
• Dulce et ___ (Horatian maxim)
• Worth using
• Like good tools
• Able to put in service
• Universal fuels designed to be beneficial
• Fuse blown at centre of bulb — that's handy
• Worthwhile American English teaching outside of university
• Blown fuse found in university - how handy is that?
• Coming in handy
• Convenient American energy extracted from coal, say, and sent North
• Able to be implemented
• Unknown in City to quit permissible working
• Frequent companion of Q, in Scrabble