Cloud GPU or own hardware?

Got a dilemma. I need GPU power once or twice a week for some model testing. Nothing running 24/7

Cloud feels like throwing money away on idle instances. But buying my own 4090 means it sits there collecting dust most of the time (and getting outdated)

Been looking into weird middle grounds too like those decentralized networks where you can rent out your GPU when not using it (Ocean Network and such)

For those who faced this what made you finally pull the trigger on buying? And if you did, do you rent it out during idle time or just let it sit?