Usually don't bother unless it's literally raining all day, wallet and phone just sitting loose in my jersey pocket. Waterproof phone (Samsung S5), it has survived full submersion several times so what's a little rain. And Canadian bills are plastic so it's not like anything in my wallet is getting ruined. The only downside is not being able to actually use my phone when it's soaked, the capacitive touchscreen gets confused - my phone's touchscreen does work through a ziploc though, so bonus points for ziplocs!