I used B-free for 8 months already and still good. If your baby is more than 6 months, I think you can remove the tube because baby should able to release the gas by himself/herself. Basically, I never depends on the tube to test temp, I test by hand. Besides, it is summer now, no need to have too hot milk for the baby
my baby have used bfree milk bottles for 8 months. I tested the temp. by myself, not depend on the colour of the tube.
As instructed by bebedream sales, the bottles should be changed for every 9 months to 1 year. Therefore, I planned to changed all bottles during the coming month