Ke tou chronou mas!

[Kratylos]

Also in religious fests you can say " H Panagia (or the name of the Saint who is celebrated) voitheia sas/mas"
For example :
"Η Παναγία βοήθειά σας/μας, και του χρόνου με υγεία!"

Monica of course you can add like you said "kai tou chronou" (without the "mas" at the end)