Using records on this site to test the 'rule of thumb' that apprenticeships were arranged to end at age 21...

Apprenticeship (abbreviated)
Baptisms (Sheffield; abbreviated)

ABDIE Abraham son of Richard 10, 1690, F. 1700 [computed dob 1779]
ABDYE, Abraham Baptised March 22, 1677, s. of Richard

BIRTLES George son of Thomas, mason; 8, 1749 [computed dob 1736]
BIRTLES, George Baptised December 26, 1736 s. Thomas (mason)

BLAGDEN, Henry son of Hy (carpenter) 8, 1752; 6-5, 1753 [computed dob 1739/1737]
BLAGDEN, Henry Baptised January 27, 1740 s. Henry (wheelwright)

BLONK John son of William 8, 1712 [computed dob 1699]
BLONKE, John Baptised March 3, 1696 s. William

BOCKING Robert son of Thos. 8, 1712 [computed dob 1699]
BOCKING, Robert Baptised March 9, 1697 s. Thomas

BREWSTER John son of Robert 10, 1693 [computed dob 1682]
BREWSTER, John Baptised November 5, 1681 s. Robert

Hugh