405. How long have you been using (CURRENT METHOD) (this time) without interruption?

315F. For how long have you been using (CURRENT METHOD) continuously?

337. For how long had you been using (LAST METHOD) before you stopped using it (last time)?

331) For how long have you been using (CURRENT METHOD) continuously?

429) How long have you used this method without interruption before stopping it?

323. For how long have you been using (CURRENT METHOD) continuously?