It depends on the market and rental income. In my market (B- and C-class) I don't install new flooring unless A) the flooring is trashed or B) I'm rewarding a good tenant who has rented for a while.
I bought my first 8-plex in April of last year. I spent all of last summer remodeling a few of the units that people moved out of. I quickly realized that I was overdoing it. These are rentals, not model homes or homes for sale. They need to like nice and clean, but don't need to have all of the fancy extras, unless that's the market you are in. I certainly am not.
@Johnathon Hendon I concur with all the above statements specifically about being time conscious and not overdoing it. I'm also active military so I know how restricted your time can be during the week. I've run into this same issue. I've also had to balance doing a repair myself versus paying a contractor. I'm at a point now where unless I know exactly how to do a specific repair (and I have the time) I just hire a professional. Otherwise the time it takes for me to research it and then slowly do the repair is more in lost rental income than if I had just hired someone in the first place. I'd recommend hiring out the repairs/upgrades and doing the cleaning yourself. The contractors can do the work during the week and you can clean it up on a weekend. You might hire out the cleaning too. Then it will be ready for a new tenant quicker and you'll start getting those rent checks sooner.
You should have considered the time factor prior to buying the place. Consider hiring some of the work out. Sure it will cost more to hire out, but your real goal is to get a tenant in the unit ASAP so it starts generating income. Vacancy is a landlords biggest expense.
@Johnathon Hendon If the vinyl is over concrete in a basement you may want to skip it. If it is in the main living area consider hiring it out to do. I would lean toward showing ASAP. The weekend and night stuff can get old but in the beginning pick off those things you are most comfortable doing. If you have a full time job don't start with 600 square foot of flooring if you never did it. Start with a smaller job and work out a timeline. If it is an additional 4 weeks not rented for you to do the floor consider paying someone to do it. time is money, it is a mistake we all make to do it ourselves when it takes longer.