Their friendship grows ever fresher with the years.
Tips
memory
Read character by character: 历久 (after long years) 弥新 (all the more new). 弥 here means 'all the more' — the longer it lasts, the fresher it feels. Used for music, art, classics, brands, and friendships.
usage
Praise/positive only — never for things that have decayed. Common in marketing copy for heritage brands and book reviews of classics.