Determine if a user is a recent donor (last 30 days) with this conditional check.

give-is-user-recent-donor

<?php

/**
 * Is User Recent Donor (Rename/Prefix)
 *
 * @description: Display Donors from Last 30 Days
 *
 * @return bool
 */
function my_give_is_user_recent_donor() {

	$recent_donor = false;

	//Only if user is logged in & if this user is a donor
	if ( is_user_logged_in() && give_has_purchases() ) {

		//Cool, they've donated... get their donation history
		$user_donations = give_get_users_purchases();

		//Sanity check
		if ( empty( $user_donations ) ) {
			return false;
		}

		//Loop through donations
		foreach ( $user_donations as $donation ) {

			//Now check if there's a donation within the last 30 days...
			if ( strtotime( $donation->post_date ) > strtotime( '-30 days' ) ) {

				//Sweet, they have... flag it!
				$recent_donor = true;

			}

		}

	}

	return $recent_donor;

}
//User the conditional function
if ( my_give_is_user_recent_donor() ) {
	//Do something...
}