StartHere robot - Arduino

I thought it was one of the rule to join the great community, so I spend this weekend to make this "Start Here" robot by using Arduino with motor shield from AdaFruit. Basically it just detect the object and turn right. There's whole lots of room could expand its ability.

The code is simple but I probably make it way too long and I alway confuse about one thing. Should I keep sending the forward command to have motor keep going or I should stop sending when there's no need to tell motor to keep going? That's why I have add "if(excute == true)" in order to have FORWARD send only once. or there's better way to do this? Thanks for any input!