[This information dates to my experience at BMT from 31 May - 1 Aug of 2011. There have since been changes to the policies regarding the frequency of phone calls, so please keep in mind that your experience may vary!]
Let's clear up all of the cell phone questions right now, since I know it's a concern if you're heading off to BMT.
Yes, bring your cell phone down to BMT and definitely remember to bring your charger. Some trainees opted to cancel their contracted plan and buy a pre-paid phone instead. That's not a bad idea, just make sure you've purchased enough minutes, or that your family members can top it off for you while you're away. If you stay with a contracted plan, make sure you look into whether they offer a military discount and take advantage of that.
You might want to opt to cancel any data plans or texting plans while you're away. You won't be authorized to do anything other than make phone calls while you're down at BMT. No looking at texts, no sending/replying to texts, no Facebook, no Tweeting, no Instagram, no pictures, no BBMs. Phone calls only. Can they see what you're doing at all times during phone calls? No, but it's an integrity issue and your integrity is everything at BMT. Trainees police themselves. If someone sees you texting, you can bet your MTI will find out eventually. Don't jeopardize losing your phone call privileges over a quick text.
You'll be able to use your phone while you're in transit to Lackland AFB, up until the point that the bus stops on base and you get off at the reception center. Take advantage of it - that's the last time you'll text, Tweet, and FB for the next eight and a half weeks.
When you arrive at your dorm, your MTI will collect your cell phones and place them in a small garage storage box with pull-out drawers, the kind used to store nuts and bolts. The box is numbered to coordinate with bed numbers, so your bed number and phone drawer number will match. I recommend placing your charger in this drawer, and take your battery out of the phone to store in the drawer as well. This will help save your battery for when you need it and will eliminate any chance that your phone might accidentally go off while in storage. Why do I mention that? Of course, it happened! On my first terror-filled night, we were woken up by a cell phone that wasn't properly turned off...and a very irate MTI who hit the lights and made everyone get out of bed.
Your very first phone call will be the "I've arrived safely" call. You'll all be handed your phones and you'll get a few minutes to read off a scripted message to your family. Once you've read off the message, you'll hang up. This is not time for stories or a catch-up. Just a quick message and an "I Love You" and you're off the phone.
Typically trainees get one fifteen minute phone call a week, normally on the weekends. The timing will never be standardized, so tell your family members to be prepared to answer the phone at any time. Welcome to the military, that's how it goes when you're deployed as well. Sometimes you'll get them, sometimes you won't. When I couldn't get my husband on the line, I'd call my dad or other close friends/family. There is a roster that you'll initial off on every time you make a call.
Your student leaders and/or Flight Office Technician (more on the "House Mouse" later) will facilitate the phone call sessions. They'll pass out phones, and don't dawdle when they do. Grab your phone and fire it up. There's always someone with a slow phone that you'll wait on. As a Dorm Chief, we eventually started going off of my timing. I would verify that everyone's phones were ready and yell "GO!" I would eyeball my phone the entire time, giving everyone a five minute warning and a one minute warning. In the end, I'd count down the last ten seconds and you had to have hung up by the time I hit one.
There will be a lot of tears after that first phone call. The first week and a half is extremely stressful, and once you get your loved ones on the phone, it gets to you.
Be mindful of your behavior, as it'll affect your phone calls. If you are a stand-out trainee, you could be rewarded with a bonus phone call, as I've mentioned before. If your flight is misbehaving or not performing up to standard, you phone call may be delayed. Don't risk it. Your flight performs better when they know a phone call is at stake.
Your phone will be (permanently) returned to you on the Monday morning when you ship to tech school. If you're lucky, you'll get it the night before. You will not have your phone during base passes or town passes with your family. I kept asking my DH or FIL to hand over their phones during our outings, so I could get my fix.
**If you choose not to bring a phone, know that you'll rarely get to make a phone call at the same time as other trainees. You'll usually have to wait for a sympathetic flight member to let you borrow their phone, and it'll have to be at the MTI's convenience, since they'll have to time your call separately. Maybe you'll have a great wingman who'll forego their call so you can use their phone during the designated time that week, but most of us don't want to put someone in that position. They'll get their call later, but still. If you're concerned about costs, find a cheap pre-paid phone. Using a calling card on the patio phones isn't typically an option, and definitely not during the designated time. I never set foot on the patio during my entire stay at BMT.**