If missing values are something which haunts you then
MICEpackage is the real friend of yours.
When we face an issue of missing values we generally go ahead with basic imputations such as replacing with 0, replacing with mean, replacing with mode etc. but each of these methods are not versatile and could result into a possible data discrepancy.
MICEpackage helps you to impute missing values by using multiple techniques, depending on the kind of data you are working with.
I’d heard of a couple of these, but most of them are new to me.