Question

If the parameters for statement 1 and 2 are identical, do I need to re-bind, or can I do this?

$stmt = $dbh->prepare("SELECT ... thing = :thing ...");
$stmt->bindParam(':thing',$thing);
$stmt->execute();
// do something with data
$stmt = $dbh->prepare("SELECT something else ... thing = :thing ...");
$stmt->execute();

?

Answer 1

Assuming you actually mean:

$stmt = $dbh->prepare("SELECT ... thing = :thing ...");
// ...

No, you are assigning $stmt to a new PDOStatement object, which does not hold the information that was stored in the old object.