Criteria for knowing "genuine" reflexive verbs

Question

While studying German grammar I learned that one of the criteria to differentiate genuine "echte" reflexive verbs from other verbs is that:

Nach dem Reflexiv Pronomen kann man nicht fragen
Source: https://youtu.be/RuUIUOOxbxc?t=128

An example given was: Ich beeile mich
To say: Wen beeile ich is not correct.

So, I was just wondering if this is correct to ask myself/self-thinking: Wann werde ich mich beeilen? (When will I hurry up?)

If yes, then how this example is not contradicting the above criteria?

Answer 1

Two examples:

Er rasiert seinen Kunden. – Wen rasiert er? – Seinen Kunden.

Er rasiert sich. – Wen rasiert er? – Sich (selbst).

Rasieren is not a reflexive verb, so it makes sense to ask for the accusative object. This doesn't change if the barber shaves himself.

Er beeilt sich.

Sich beeilen is a reflexive verb. It makes no sense to ask for an accusative object, it must be the same person as the subject. There isn't another person or object involved in the action beeilen. Someone can only do this to himself.

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Wann werde ich mich beeilen?

You are not asking for the accusative object, but for an adverbial of time. That's okay and congruent with the rule you just learned. It makes no sense to ask

Wen werde ich beeilen?

because beeilen does not manipulate an object but the subject itself.