Signs you need hock injections...

I haven’t done hock injections before but I am beginning to think it might be time. What signs/symptoms made you look into getting hock injections?

Horse (show hunter) was reluctant and/or late to lead change behind. Vet looked at her, watched her go on the lunge, and we did hind flexions. Also, age and workload of horse (12yo, 3’3-3’6 courses as an AO hunter). All these in combination made us decide to do hock injections. Worked like a charm. Horsie is happy and lead changes are clean again.