Sometimes i've read, it's important to tell your doctor about any "changes in your bowel habits", what does that mean? what changes are concerning?

Bowel habit means the characteristics of your daily bowel movement, e.g. how often you have bowel movement, how are your stool consistency, form, color and quantity, etc. So if there are deviations from the normal characters such as from daily bowel movement to only 2 or 3 a week or change in the form, consistency or color of your stool then those are changes in bowel habits. Take care.