How many times can pleural effusion be drained without coming back?

No limit. Generally, no limit on "how many times". However, the more times someone undergoes an invasive procedure the greater risk of complications. Key to preventing recurrence is answering "why did you get the effusion? ". Then treat the primary cause. Be well.
Depends. Mainly on why you got it. An effusion from cancer or heart failure isn't going to go away permanently.

Related Questions

Can you let me know how many times can pleural effusion be drained?

Many. But better to get it fully drained once, and the cause identified and treated to prevent the recurrence. Some cannot be stopped, but can be internally drained with devices.
As many as..., but. Draining effusion is a part of symptomatic care, which may be done as many/often as clinically needed, but comes with increasing complications such as infection, pain, etc. Due to its often related-with chronically debilitating illnesses in attesting life is a one-way street of accumulation, modification, & continuation. So, ask more concerns or issues with the treating doctors.

How many times can pleural effusion in a baby be drained?

As many as needed. As many times as needed until correction of the causative process can be addressed. Question is too inespecific to give context to a more thorough explanation and answer.
No limit. Generally, no limit on "how many times". However, the more times someone undergoes an invasive procedure the greater risk of complications. Key to preventing recurrence is answering "why the baby developed an effusion? ". Then treat the primary cause. Be well.