[рони]

Кристиан,
сохранение на сутки, expires: 1,

<script src="https://ajax.googleapis.com/ajax/libs/jquery/1.12.4/jquery.min.js"></script>
<script src="https://cdnjs.cloudflare.com/ajax/libs/jquery-cookie/1.4.1/jquery.cookie.min.js"></script>
<script>
$(function() {
    var nCount = $.cookie("user_count") != undefined ? $.cookie("user_count", Number) : 0;

    function open() {
        if (nCount % 2 != 0) {
            $("#menuicon a:before").addClass("bchanged");
            $("#menuicon a:after").addClass("achanged");
            $("span").addClass("schanged")
        } else {
            $("#menuicon a:before").removeClass("bchanged");
            $("#menuicon a:after").removeClass("achanged");
            $("span").removeClass("schanged")
        }
    }
    open();
    $("#menuicon").click(function() {
        nCount++;
        $.cookie("user_count", nCount, {
            expires: 1,
            path: "/"
        });
        open()
    })
});
</script>