Is it safe to jailbreak my iPhone 4s?

I have an iPhone 4s with sprint and I was wondering if it is safe to jailbreak it because a few months ago I jailbroke it with green posion and it worked for about 2 days then it woulnt let make call or send text or download apps from installous. Sprint and apple couldn't figure out what was wrong or how to fix it (i deleted cydia) so they just gave me a new Phone. After that my dad said if I jailbreak it again I'm not getting a new one, so I want to know when is it a good time to jailbreak it with guarantees of it not doing what it did to my last iPhone and what program should I use next time?

How to get the cydia icon back on my iphone?

I deleted cydia off my iphone 4 that i bought not knowing what it was and i ended up needing it to unlock my phone but i went to the cydia account and deleted the icon and i've tried rejailbreaking it but it won't because its alredy jailbroken and i've tried master resteting it but its taken more than an entire day so i need help thanks

Why isn't Tool- sober on iTunes?

I can't even find their Undertow album in stores… I have an iPhone and i don't know of any free music sites or apps either. Any suggestions?

How to change my itunes account on my iPhone?

I just got my dad's old iPhone 4S. He had already set up the iPhone using his iTunes account.Me and my dad like very different music and all of mine is set up on my iTunes. I don't want to erase everything because my contacts have been uploaded, my pictures, and I don't want to lose them all. Is there any way I can remove my dad's account on my iPhone and add mine on?

Switching from blackberry to iPhone?

So I got the new blackberry curve a few months ago on a 3 year contract (so its still under warrantee) but now I've decided that I hate it and want an iPhone
is it possible for me to switch my phone out for an iPhone 4S?
My phone was free with a 3 year plan, and the iPhone is 159 with a 3 year plan. So would I just have to pay the 159 for it and be done, or is it more complicated than that?
I was planning on taking my phone in regardless because it is increidablly laggy, the battery life is terrible, and it randomly stops and has the loading timer thing when I'm typing

I have a telus phone if that makes a difference

How come my pictures aren't sending?

I have an iPhone 4s. The picture messaging was working fine up until last week, now my pictures won't go through. I tried sending a picture to my friend and the sending bar went up almost all the way then a red exclamation point popped up. I checked my settings, and turned off the MMS then back on and nothing happened. I also shut off my phone and then turned it back on but it still doesn't work.

Will the iPhone 4S price go down?

With AT&T, the iPhone 4S (32gb) is $199 instead of $299 with a discounted upgrade, I just talked to an employee. I heard that the iPhone 4S will go down in price $100 everywhere because of the iPhone 5. So, if I use my upgrade after the iPhone 5, will my discounted price be $99 instead of $199?