Based on your financial expertise, provide your response or viewpoint on the given financial question or topic. The response format is open.

What are the pros and cons of buying an item on installments with zero percent interest?
One small advantage to paying ahead is having an outstanding installment plan may preclude unlocking the phone for use on other carriers, for example during international travel. If unlocking is important, researching the particulars would be in order. I am more familiar with T-Mobile, and will use as a specific example. If I pay upfront, I can purchase the phone from Apple totally unlocked, and T-Mobile has no say in whether I use it on another carrier or not. (This actually costs a little more, because the phone from Apple doesn't come with a SIM, and T-Mobile charges for the SIM. At least as of iPhone 5s.) Looking at "Unlock your mobile wireless device, Unlock Requirements" on T-Mobile's website, at least some payment plans do not allow unlock until the phone is paid off. Obviously phones purchased for full price from T-Mobile start out paid off.