An informal abbreviation of the proverb 'Chiri mo tsumoreba yama to naru' meaning that small amounts add up to something large; used colloquially.
毎日節約すればいつか貯金になるよ。ちりつもだね。
If you save a little each day it will become savings someday. Every little helps.
ゴミを分別するだけでも、長い目で見れば効果はある。ちりつもだ。
Even just sorting trash has an effect in the long run. Every bit counts.
英単語を一日五個覚えるのを続ければ、半年でかなり伸びるよ。ちりつも、だね。
If you keep learning five English words a day, you'll improve a lot in six months. Little by little.