How Often Should Bonding Be Replaced?

The short answer is, 'yes'.  You can bond at the gumline, but it usually doesn't last long.  Your gums receded probably due to brushing too hard and having a thin layer of underlying bone (called by dentists "a thin bone type").  A better solution would be to have a periodontist cover the ex...

The cost would be around $150-$300 each. You would nee to add fillings to both teeth for it to look esthetically pleasing. Have you Ever considered short term Invisilign, it would bne a better option. This is because the 2 fillings you need, due to thier location, can easily chip and also discolor.

It sounds like you did bonding to widen your teeth and close gaps.  The dentist most likely did not remove any tooth structutre, so this bonding can be safely removed and your teeth restored to their natural size and contour.  Once that is done, you are free to get your orthodontics...