Best / Worst Capex affecting NOI on a MF reposition

Hello All,

What would you say has been the best returns / worsts Capex investments done in terms of impact on the NOI. We have taken possession of a MF that has been poorly managed for the past few years + a lot of differed maintenance + undervalued rent (previous owners didn't put a $ in the property but also didn't increase rents). Our current plan is to do the urgent structural repairs + renovate units as they become vacant (Kitchen/bathrooms/fixtures...). We also have a vision for the common areas / elevator / parking, however I would like to get your opinion on how to prioritize the different Capex/renovations in a MF repositioning plan, what has work well for you in past deals and what hasn't been worth the investment.

Thanks