First rental coming so I staged the unit before listing it, 1,200 in, gone in 9 days at full ask

Columbus rental market is tight enough in the under-1,600 bracket that you probably would have leased it either way, but nine days at full ask with zero negotiation in March is genuinely strong regardless of what caused it. The photo comment from three separate applicants is the real data point there. That tells you the 1,200 spent on a couple of rooms translated directly into click-through, which is where Columbus rentals either die or survive right now given how much of the search happens on Zillow before anyone calls. August is a different animal though. You're hitting turnover right at peak rental season in a college-adjacent market, so the lift from staging might compress because demand is just higher across the board anyway. If I were running that experiment I'd probably list the second unit empty in August just to actually have a comp, because you're right that you only had one shot at the first one and you still don't know what the counterfactual looked like.

The photos angle is real and I think undersold in most of these conversations. My brother and I did a full rehab on a brick two-flat in Cleveland, listed it empty first because we ran out of time, sat for 23 days with lowball offers coming in. Pulled it, spent about 900 on a partial stage, same living room and bedroom approach you did, rephotographed on a Saturday morning with better light, and had a signed lease at our number inside two weeks. Same unit, same ask, same neighborhood. The only variable was how it read on a screen.

The August question is the one I would actually think hard about. March in Columbus is a different animal than August, you are probably still catching the summer move wave but it starts thinning out toward September, so if the unit does not move fast you are eating vacancy through the slow stretch. The 1,200 you spent in March was easy math against 1,475 a month because you had urgency working for you from the seasonal demand side. In August you might want the stage as insurance against a longer sit rather than as a conversion tool for a hot market, which actually makes the case for it stronger, not weaker. I would not use August as the clean test against March. The markets are not the same.