Can I stop paying rent if repairs aren't done?

Short answer: the law determines when and whether the "tenant's obligation to pay the full amount of rent stops" and the laws vary.

In specific (and rare) instances, after proper written notice, etc,  tenant MIGHT be authorized to withhold rent by placing it in an escrow account for future distribution by a court order.  Yes, it's possible for a court to order the landlord to do the repairs AND deprive them of some or all of the rent, but more likely the court will hear evidence of the value received by the tenant versus the severity of "habitability issues". 

In severe cases the health or building department may actually order tenants to leave, thus SUSPENDING the obligation to pay rent, under the theory that the landlord has frustrated the intent of the lease by allowing conditions to deteriorate to that stage. Again, it's then up to a court to determine what, if any, refund the tenants get, or how much the landlord gets.

In NO CASE can you be "evicted" for non-payment of rent. That's a myth. You can be notified of termination of your tenancy and REQUESTED to leave, due to non-payment. That is not "eviction".  Only if you REFUSE to leave does the  law generally require a landlord to obtain an order of eviction from the court.

You may be "summarily removed" from the premises for various serious violations amounting to criminal violence, but you're still not "evicted" until a court rules that you no longer have the legal right to live there.

I have been in this situation before, I spoke to my landlord very nicely and said that I would be happy to pay and get the repairs done myself if he didn't have time and I would take the money out of the rent! He had the repairs done within a week

No you can not do this.  If you do - then you will be evicted.

That varies from state to state.

You don't have this right EVERYWHERE. Only some states allow you to withhold rent for lack of repairs. You need to find out before you try it if your state allows it as a remedy for landlord neglect. 

AND--you can't simply NOT PAY IT. You have to pay your rent into an escrow account--such as one you set up with the Clerk of Courts. That's the tricky part--you can't just STOP PAYING. And you also will have to document any times you contacted the landlord about repairs that weren't made. So good luck--but don't use this as an excuse not to pay rent. 

read your contract and learn the rules and responsabities first . if the plce is uninhabital then why are you there , move .

Zero did you just become a realtor Troll, asking and answering your own questions?  Do you realize this is against community guidelines?

You should be aware that this practice differs by state, as the real estate laws of each state differs, so be careful about your universal statements.  Good luck in your future.

If the unit is uninhabitable, you can't live there.

If you can live there, the unit is habitable.

If you live there, you owe rent.

Only in a few places in the USA is it legal for the tenant to withhold rent and that's under VERY specific circumstances and usually the rent must be paid into an escrow account.

Laws vary by location.

I can't tell if you're actually asking a question or if the title was just there so you could post your statement. So I'll just say that laws on the matter vary by location.

As a tenant if you're going to withhold rent you better be damn sure you've done everything right because otherwise you'll end up with an eviction and judgement on your credit report.

Local laws apply here. Generally speaking, the tenant cannot simply decide on their own to withhold rent. In my state, except for one city, withholding rent for repairs is illegal and grounds for eviction. Since you don’t tell us where you are, nobody can accurately tell you if you can legally withhold rent for repairs or not.