[Help-bash] When to use exec to run a program?

[Peng Yu]

Hi, I've read the description here. For exec, I see many scripts in
which the last externally command is exec'ed, which saves one fork()
call, hence should be faster.

https://lists.gnu.org/archive/html/help-bash/2015-08/msg00014.html

In this case, should I always use exec whenever possible? For example,
would something like the following be preferred in a pipeline?

exec cmd1 | exec cmd2

Or exec should not be used in the case of pipeline.

cmd1 | cmd2

What about the usage of <(exec cmd)? Is it recommended?

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Regards,
Peng