I rarely hear it anymore. It is not taught at my facility and I have never heard a coworker use it, but we work IFR jet traffic almost exclusively. A few examples I could think of where it would be used, speaking from pilot experience only:
VFR aircraft that accepts a vector and the vector is no longer needed
ATC: [traffic call]
VFR: negative contact
ATC: suggest you fly heading 090
VFR: roger, heading 090
[time passes]
ATC: traffic no longer a factor, resume own navigation.
The other instance I could think of is a non-GPS equipped IFR flight that is off route for whatever reason and needs help getting back on route, or to put it more simply, a flight that cannot accept a direct to fix clearance:
ATC: Fly heading 090 until FUBAR, then resume own navigation