تُبْـلِي وَيُـخْـلِـفُ اللهُ تَعَـالَـى
Tublī wa yukhliful-lāhu ta`ālā.
Translation
May you wear it out and Allah تعالى replace it (with another).’
The intended meaning: A supplication for long life.
When to recite
Said to someone wearing new clothes
Source / Reference
Hisnul Muslim 7