Regardless of what type of IRA you have there will always be a limit on how much you can contribute to it annually. Your contributions do not have to be all in one lump sum. You can divide the maximum limit by 12 and have 12 different deposits into your IRA each and every year or if you want to do it quarterly then you can deposit 4 different times per year. The main point is that you max out your IRA because this money will never be taxed.

The max contribution an individual can make to their IRA regardless of whether it's a Traditional or Roth is $5,000 for people 49 years old and below. People that are ages 50 and above can contribute an extra $1,000 per year along with the $5,000 for a total of $6,000.

After 2008, the contribution limit will raise in increments of $500 depending upon the level of inflation. You cannot contribute more than the max amount per fiscal year. So for example, if you put in $3,500 into your IRA last year and this year you want to add the extra $1,500 to last years deposits while you include the $5,000 for this year. There will be no way that you can do that. Each and every year your max will be $5,000 (or more if raised by the government).