For one of my projects, a clean default dev profile gives:
Finished `dev` profile [unoptimized + debuginfo] target(s) in 6m 12s
A clean debug = "line-tables-only" build:
Finished `dev` profile [unoptimized + debuginfo] target(s) in 5m 02s
With the default profile, after touching main.rs/lib.rs:
Finished `dev` profile [unoptimized + debuginfo] target(s) in 16.59s
With debug = "line-tables-only", after touching main.rs/lib.rs:
Finished `dev` profile [unoptimized + debuginfo] target(s) in 14.21s