"I think it is time to buy a washing machine."
Translation:Tôi nghĩ đến lúc phải mua một cái máy giặt rồi.
Is "rồi" always necessary at the end of the sentence in this structure?
... đến lúc phải ... rồi
You can use thôi but the nuance is a little different. For example:
"Anh nghĩ là đã đến lúc hai đứa mình nên chia tay thôi" = I think it's about time we go our separate ways (already).
Thôi emphasises the fact that it's the best option while rồi is more of that it should've been done sooner. .
Keep in mind not everyone has one especially in a developing country like Vietnam though times are a changin'. :)
TehVanarch I must thank you for your many helpful comments in the Vietnamese course, I've seen a lot of them recently.