THEME: short E sound substituted for by A sound in familiar phrases
GOOD ONES: "Leave tiny bugs alone"? DON’T SW
AT THE SMALL THINGS
Moderate building expansion? LIMITED
ADDITION
Former "formerly" ERST [oldie but goodie]
Sketch opening ETCH-A- [not comic routine]
Sound of silence? SHH
Introduction to a madam? I'M ADAM [as in "Madam, I'm Adam"]
BTW: PUT A FATHER IN YOUR CAP took me a second --- it's idiomatic: put someone in = put on someone --- sounds too much like high fashion for this lowlife
Counts'
equals EARLS [counts are not English and are not part of the peerage; the clue needs "abroad"]
Word in many music genres METAL [I must be "out of it" since I know of only one: heavy. Can there really be many?]
Bygone blade SNEE [For me, the highlight of this puzzle is that it also gives us SMEE, which seems to damn with faint praise.]
RATING:
Three grins = Loved it; Two grins = Enjoyed it; One grin = A bit bland for my taste; One teardrop = Not much fun