Paid Memberships Pro - This function will output the number of days left in a trial period for a user in the member links section on the account page.

gistfile1.txt

/**
 * This function will output the number of days left in a trial period for a user in the
 * member links section on the account page.
 */
add_action( 'pmpro_member_links_top', 'my_pmpro_member_links_top' );
function my_pmpro_member_links_top() {
	// Get current level details
	$user_level = pmpro_getMembershipLevelForUser();

	// Make sure we have a trial
	if ( $user_level->trial_limit != 0 ) {
		// Trial ending time (UNIX Timestamp)
		$trial_end_time = strtotime( '+' . $user_level->trial_limit . ' ' . $user_level->cycle_period, $user_level->startdate );

		// Make sure the trial end time is after the current time
		if ( $trial_end_time > time() ) {
			$current_date = new DateTime( 'now' ); // Current date
			$trial_end_date = new DateTime( date( 'Y-m-d', $trial_end_time ) ); // Trial end date
			$interval = $current_date->diff( $trial_end_date ); // Compare the two dates
			echo '<li>Your trial period ends in: ' . $interval->format( '%a days' ) . '</li>'; // Output to user
		}
	}
}