What is the optimal maximum amount of elseifs in one if statement to manage them easily?

Answer 1

you can use as amany as u wish but i suggest the switch is best

Answer 2

If you find yourself using a lot of "elseif"s like this

<?php
if ($a > $b) {
echo "a is bigger than b";
} elseif ($a == $b) {
echo "a is equal to b";
} elseif (...) {
echo "...";
} elseif (...) {
echo "...";
} elseif (...) {
echo "";
} elseif (...) {
echo "";
} else {
echo "a is smaller than b";
}
?>

then you should look at using switch construction instead:
http://php.net/manual/en/control-structures.switch.php