bit-by-bit in small stages piecemeal step-by-step stepwise
bit-by-bit%5:00:00:gradual:01 in_small_stages%5:00:00:gradual:01 piecemeal%5:00:00:gradual:01 step-by-step%5:00:00:gradual:01 stepwise%5:00:00:gradual:01
one thing at a time