No, never even thought to do this tbh. only place I say keep the change is in taxis..and mainly as the drivers huff on while getting the change
Will round up long journeys to the nearest tenner (like we went to south shields a few weeks badck and it was 34 quid so just gave 40) and shorter ones it depends what I have on me, generally just to the nearest quid unless they help bringing shopping in and that in which case i give more as thats them doing extra thats not their job really.