Does jailbreaking your iPhone always mess it up?

I've jailbroken my iPhone, and i've installed ONE tweak. This is the only thing i plan on installing, and i don't plan on ever opening cydia again. Jailbreaking my old iPod has reduced it to taking 30 seconds just to open up settings, so i don't want this to happen to me relatively new iPhone 5.So anyways, If i only have that one thing downloaded will my phone get messed up at all?

How to put a lock on my iphone?

I'm not really sure what kind of iphone it is- it's more clunky than the newer ones, so I'm thinking it's the earlier one.

I've tried looking through all the stuff in my phone to see if I can lock it- but I can't find anything? Can you lock the old ones?

Iphone data usage with pre-paid phone?

I just got an iphone and i have a telstra long life deal in which i have $30 worth of credit for 6 months (mainly use viber and what's app and my home Wi-Fi) but since yesterday it says i've used up $15.00 worth! What do I do? Never had a pre paid phone so don't know how this even works. HOW CAN I REDUCE DATA CONSUMPTION! #FreakingOut (that went into caps accidently but it helps emphasise how i feel i guess?) so yeah thats about it. I BEG YOU FOR Help lol

Blocked Calls on the iPhone?

**Please ANSWER, READ DESCRIPTION**

When you *67 a number on your iPhone it still shows the contacts name like your calling the contact without your number being blocked or withheld.

Like when you type in (example) *67-555-5555 it shows their contact name, Frank, like your calling Frank without your number being blocked or anything.

My question is, when you call that person with *67, does your number show up blocked on their phone?

Can i use my iPhone 5 headphones as a mic?

I was skyping my friend yesterday and was wondering if I could use my earpods as a mic on my laptop. I know I can on my phone for recordings, but wondered if I could use them on my laptop.

Unlocked iPhone 4 on T-mobile?

I have a factory unlocked iPhone 4 that I'm currently using on T-mobile. I don't have a data plan, because the iPhone was originally not part of T-mobile, you could use it and they didn't charge you with a data plan because it showed up as an "unknown device", if it was unlocked. But now that the iPhone 5 is out on T-mobile, will they force me to get a data plan on my iPhone 4?

How to make app icons customized on iPhone?

So I was looking on my friend's iPhone and I see she has all her apps in customized fonts, colors, and prints. She told me she got an app, but won't tell me what it's called. I know her phone isn't jailbroken either and it's NOT called cocoppa!