Carry yarn and chnaging colour yarn in colour work from row to row

My recent re - project, Squarely Mamushi, has given me a chance to take a deeper look into the relationship between slip stitch selvedge, changing colour yarn and carrying colour yarn from row to row

My old habit in selvedge will be starting the row with sl1wyif and last k1 at end of++ row.  When changing colour yarn in knitting in stripes, I like to do it at last stitch in WS row.  When this is done in every other row, e.g., in mosaic knitting, nothing much to say.  In situation where it will be 2 rows or more in changing colour yarns, both carry yarn along the edge and changing the colour yarn is something that might lead to a little discussion