Nobody can promise you a date
Anyone quoting a firm timeline is guessing. Times change with volume, policy, and office. USCIS publishes current processing times by form and by office, and the National Visa Center and each consulate publish their own. Those are the numbers to use.
What changes the timeline most
Whether the petitioner is a US citizen or a permanent resident, because that determines whether a visa is immediately available or whether the case waits in a preference category. Whether the applicant adjusts status here or processes at a consulate. Which office handles it. And whether the filing was complete.
The part you control
A complete, consistent, well-documented filing avoids requests for evidence, and requests for evidence are the single largest avoidable delay. Keeping your address current and answering every notice promptly is the rest of it.
Interim benefits
Where adjustment of status applies, work and travel authorisation can usually be requested with the application, which changes what the wait feels like even when it does not shorten it.
