It is not rude to ask for time off in advance. In fact, it is generally considered courteous and professional to give your employer or supervisor as much notice as possible when requesting time off for a vacation or any other personal reasons.
By asking for time off in advance, you allow your employer to plan and make arrangements for your absence, ensuring that the workflow is managed efficiently. This proactive approach also shows that you respect your employer's time and value the work you do within the organization.
On the other hand, if you just say "I'm going on vacation" without providing prior notice and then request time off when you get back, it may be perceived as inconsiderate and disruptive. Your employer might have already scheduled tasks or assigned responsibilities to you during the time you were away, and your sudden absence could cause inconvenience or delay in the workflow.
Additionally, some companies have specific policies regarding time-off requests, such as requiring a minimum notice period or a certain number of days' advance notice for vacation requests. Not adhering to such policies could lead to misunderstandings or potential disciplinary actions.
To maintain a positive and professional relationship with your employer, it's best to request time off in advance and communicate your plans as early as possible. This shows responsibility and consideration for the needs of the organization and your colleagues.