<fieldset>
    <div class="col-md-6 test-one"><label><input id="example-category-1" type="checkbox" value="first-checkbox" />CHOOSE CATEGORY 1</label></div>
    <div class="col-md-6 test-one"><label><input id="example-category-2" type="checkbox" value="second-checkbox" />CHOOSE CATEGORY 2</label></div>
</fieldset>

var test = true;
    $(".test-one").change(function() {
        if(test){
            $('div[data-product]').parents("li").hide();
            //hide every product after first click on any checkbox

            if( $('#example-category-1').is(':checked') ) {
            //check for checkbox activation and show products if true
                $('div[data-product="1802"]').parents("li").show();
                $('div[data-product="1781"]').parents("li").show();
            }
            if( $('#category-2').is(':checked') ) {
            //check for checkbox activation and show products if true
                $('div[data-product="1348"]').parents("li").show();
                $('div[data-product="1347"]').parents("li").show();
            }
            test =false;
            //set to false so we don't enter this if statement again
        }
    });

$('#example-category-1').click(function() {
        if( $(this).is(':checked') ) {
            $('div[data-product="1802"]').parents("li").show();
            $('div[data-product="1781"]').parents("li").show();
        } else {
            $('div[data-product="1802"]').parents("li").hide();
            $('div[data-product="1781"]').parents("li").hide();
        }
    });
    $('#example-category-2').click(function() {
        if( $(this).is(':checked') ) {
            $('div[data-product="1348"]').parents("li").show();
            $('div[data-product="1347"]').parents("li").show();
        } else {
            $('div[data-product="1348"]').parents("li").hide();
            $('div[data-product="1347"]').parents("li").hide();
        }
    });