Questions & Answers about Перед выходом я всегда смотрю, выключен ли свет.
Because the preposition перед usually requires the instrumental case when it means before / in front of.
So:
- выход = exit, leaving
- перед выходом = before leaving / before going out
The form выходом is the instrumental singular of выход.
This is a very common pattern:
- перед работой = before work
- перед ужином = before dinner
- перед сном = before sleep / before bed
So перед выходом is a normal Russian way to say before leaving.
Here выход means going out / leaving, not the physical exit door.
So перед выходом is best understood as:
- before leaving
- before going out
Russian often uses a noun where English might prefer a verb phrase. Compare:
- Перед выходом я... = Before leaving, I...
- Перед отъездом я... = Before departing, I...
So even though выход can mean exit, in this sentence it refers to the action/event of leaving.