@Leora MerrellThis is what I use in the last 3 years, works like a charm, replace regular AAA battery every 6 months .https://www.amazon.com/SoHoMiLL-Electronic-Connected-YL-99/dp/B00HLVGO7Y

When I work out the different scenarios, I see that they are asking for a rent reduction that will cost me roughly the same as it would cost me to replace them with another tenant.

I just tell them they must honor the agreement they signed, however, I would attempt to also work with them by aggressively look for a replacement...but, they are stuck with the agreement until I find that replacement.Now, if you've ever tried to show a rental with a tenant inside, you know how hard that is to do. 

Due to a bad window replacement and siding job back in 2016, water was been coming in around the south facing windows every bad rain storm (like once a week in the PNW).

The gas company replaced the meter and all was well.

It's all situational.Quality location and reasonable rents when buying can insulate landlords some if a replacement is needed down the road in the future.

@Deborah Repaskey Buying a house that is 70 years old is getting better every year, one of the biggest issues with older homes tends to be knob and tube wiring or plumbing that isn't copper, both of these really started to be changed to modern standards starting in the 50s so that decade can sometimes be a mixed bag but those are going to be your primary concern unless someone hasn't replaced a major system like a roof in 70 years. 

Replacing bathroom vanity etc-Therefore I am interested to know what YOU first learned to do when you started.OR even better..tell me what you thought would be an easy DIY that turned out to be not so easy!

So all the floors in the property will be replaced and some ceiling will be replaced. 

These are reserves that you set aside every month, so that when something eventually needs replacement (i.e. roofs, foundation, HVAC, electrical, plumbing, etc.), you have the reserves set aside to pay for it without killing your cash flow for the year.