Importance of memorizing tone markings

For the conversations in the early lessons, how important is it to make sure you know every single tone marking when you do the "Write It!" exercise? I've been trying to make sure I know all the markings, but I wonder if maybe I'm wasting my time because maybe once I'm further along it will come more naturally. And I'm not so much talking about the ones that are pronounced in the recordings; I don't have trouble if it's clear in the recording. But the ones that I'm wondering if I should stop bothering with, are the ones where, for instance, it's a first tone and the speaker doesn't raise her pitch for it.

You really, really need to learn the proper tones. It is important for speech and writing pinyin. The "Write It!" exercises help (force) you to learn them. Consider these two sentences: 我买蔬菜. (Wǒ mǎi shūcài.) 我卖蔬菜．(Wǒ mài shūcài.) The first sentence is "I buy vegetables." The second sentence is "I sell vegetables." The only difference is the tone for the second word. Also, if you don't speak distinctively with the appropriate tones, your Chinese won't sound very Chinese. Finally, you do need to learn a few of the rules like if you have two consecutive low tones, the first becomes rising. However, you still write both as low tones in the Pinyin, e.g. 你好 (nǐ hǎo).

Thank-you, that helps a lot. What was confusing me was the rules you mentioned in your last paragraph; I wasn't aware of that. I think I'll try to make more progress on the Language and Culture lessons until I learn those rules, because that will make memorization far easier. Thanks again.