How to select and store avocados
A ripe, ready-to-eat avocado is slightly soft but not squishy. Look for avocados with a slight neck (not rounded on top) because those ripened longer on the tree, which means they'll taste better.
A firmer, less mature avocado is less likely to have bruises and can be ripened at home. Place it in a paper bag at room temperature and it'll ripen in two to five days, depending on where you live. Stick a banana or apple in with it to speed up the process. These fruits emit ethylene gas, which spurs ripening.
Once ripe, avocados can be kept refrigerated for up to a week.