Avocado

I found a market near my place that sells fresh avocado and i love it so i thought of buying a lot and store them in the fridge but I never "owned" avocado so I need some advice... - How much will an avocado last in my fridge? - Can I pre-peel and cut them and store them in a tupper-ware in the fridge? - Should I buy them when they are hard to touch or when they are slightly 'bland'? - if I put them in my bento will they get brown? Should I wash them with lemon juice first? any bento-friendly recipe involving avocado will be VERY welcome! ^^ Thanks in advance! ^^
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