It's been my experience (upright bassist) that solo musicians who usually practice alone sometimes begin to take “liberties” with the tempo. While they truly believe they are just being expressive and emotive, they fail to consider the possibility that they may be actually slowing down at the hard parts and speeding up at the easy parts.

This can make it “adventurous” for their occasional accompanists.

The way to avoid this situation is to practice against a steady time reference (in addition to your tapping foot).

The iReal pro player offers a range of choices from metronomic to full band, drums only or just a tasty bass line (my favorite).

https://technimo.helpshift.com/hc/en...trument/?p=ios

https://technimo.helpshift.com/hc/en...tronome/?p=ios

)BOB