Minimum a week or two. Depends though on whether it’s currently uncomfortable.
Sometimes useful, a bit of activity to fuse images. Neon at night works great, like an alarm clock in the dark, giving your brain some time to fuse the image. Some people like looking at candles in the dark as well.
Not a definitive thing but if you made an adjustment, a bit of conscious focus on fusing simple ghosting can help at times.