Fred: I always tip the owner of my hair salon a full 20% as I am afraid he'll cut my ear lobe off or give me lousy cut knowing I did not tip on previous visits - when Tony and I have toured alone we have tipped 15% - with others I never figure out the bill just ask what do I owe? I remember we had 6 hr tour from ship into Rome (just two of us) - $500 it was excellent but we thought $75 tip was fine!!!
