Should I rent a hotel or apartment in Da Nang for long-term stay?

I think an apartment would be a better option. You'll have more space and privacy, and you can save money on food and booze by cooking in your own kitchen and using your own fridge. Plus, you can negotiate a longer-term deal with the owner if you like the place. You could even try renting an Airbnb for a week or so to see if it's a good fit before committing to a longer-term contract.

If you're okay with a studio-type space, a hotel might be a good choice. But if you need a one-bedroom apartment with a washer, I'd recommend looking into Airbnb options.

If you've never been to Da Nang before, I'd recommend booking a hotel for a week to get a feel for the city before committing to a long-term apartment. Location is especially important here because of the constant construction - what was a quiet street last week might be a noisy construction site the next week. Look for a place that's not near any construction sites.