I read somewhere that it is not advisable to warm a car everyday if you're not driving around with it everyday.
But then also somewhere else it was purported you warm it everyday.

Which is the good advise and if it is to warm it daily, how many minutes worth of warming daily is enough?

If your battery is strong and your vehicle doesn't do parasitic drain, the battery would still maintain its juice for a week or more.
During raining season its advisable to charge the battery often because low temperatures affect battery performance.

Best practice though is to remove the terminals from the battery for cars in storage (long parking due to no or less use by owner)