Getting a US visa is a dream for many. There are lots of myths and misconceptions people have relating to US visas.
Here are a few:

1. One must travel within 6 months of visa grant, else visa will become invalid.

This is completely untrue. Visa has a expiry date and is valid to travel any time before the expiry date, unless it is revoked or cancelled by the U.S. immigration authorities for some reason.

2. There is a limit on the number of visas given out per year.

There is no limit on non-immigrant visitor/tourist visa. The limitation is on immigrant visas.

3. If all children are in the USA, then visa will not be granted for the parents.

This may be a valid concern for the consulate authorities, however this is not the only criteria for visa denial. If all conditions match a genuine case then you do get the visa.

4. If visa was refused in the past, a letter from a US congressmen or senator can get you a visa.

NO. The United States law assigns the responsibility for issuance or refusal of visas to consular officers overseas. They have the final say on all visa cases. Additionally, United States law is designed to insulate the decisions in visa cases from outside influences. An applicant can influence a reversal of a prior denial only through presentation of new convincing evidence of strong ties.

5. If any child is a US citizen, visitor visa will be denied for the parents.

This is not true. Any genuine case that demonstrates and proves the purpose of the travel is temporary and has no intension to stay back in USA forever will get the visa.

6. If you request a 6 month visa you have less chances of a visa grant.

The length of trip requested in visa application should justify the purpose of your trip logically. If the applicant is employed and has a 2 months leave sanction letter and is requesting for a 6 months visa, it will certainly raise questions about the intention of the visit.

7. If you were refused of any visa in the past, it is unlikely to get the visa.

There are certain conditions and qualifying criteria for visa granting, which depends on many factors and can include your denials in the past. Although, any past visa refusal doesn't necessarily have a negative impact on your next attempt. All genuine cases do get the visa if all conditions are matched.
At the time of visa refusal, the consulate officers do tell the reason for the visa refusal. If you think that you have overcome that situation and now meet the conditions you may get the visa next time.

8. If you have traveled in the past to some other countries, you will get the US visa.

Not true. US visa has certain qualifying criteria which must be met in order to get the US visa. Just because you have visa for other countries does not make your case any stronger.

9. If you had a US visa in the past, getting the visa next time is guaranteed.

Not necessarily, the conditions and situations changes. Each time you apply for visa the conditions should match with the requirements. If in the past you have overstayed, or acquired a criminal record, or violated any other rules, or didn't have sufficient funds, etc, it may have an adverse affect on your next visa application.

10. If you apply for a B1/B2 visa extension, next time your visa will be cancelled.

Not entirely true. First of all try not to overstay and leave the USA within the allowed stay period (Form I-94 expiry date). Overstay can have serious problems Unless you have applied for an extension.

Any overstay can lead to:

  • Adverse effect on your next visa application.
  • More extensive questions and answers at POE (port of entry) on your next trip. You could be denied entry to USA if you can not satisfy the officer at POE. Must keep all the documents and copies of extension/I94 etc if applied for extension during any of your prior trips.