Price-to-Book Ratio chart in different timeframes

We use different timeframes based on our time horizon and holding period.

Let's take Keppel DC REIT (KepDC) as an example using the 5-year historical P/B Ratio chart:
Notice how KepDC is currently trading at a "Very Expensive" range? This is based on its historical trading range in the last 5 years. However, a lot of have changed in the last 5 years. Just 4 years ago when KepDC was introduced to the market, many investors didn't understand this new asset class. Hence, it traded based on what the market understood the REIT to be. But over time, investors learnt of the stickiness of tenants, more aware of the growing cloud computing trend and also KepDC's fast acquisitions and growth leading investors to bid up the price. Also in 2020, with the COVID-19 situation, investors are now even more aware of the importance of the internet as a tool to bridge communications and data centres are as the heart of the internet and internet based software and services. Hence, KepDC has been a huge beneficiary of the explosion in cloud computing trend.
Therefore looking at a 5-year time frame (it's a relatively young REIT with only 4 years of history) may not give you the relevant point of view to invest in today's context. Notice how during the massive correction in Feb and Mar, KepDC did not even correct to the orange mid line!
However if you instead look at the 1-year context, then the chart paints a very different story. The data sheds off the irrelevant information historically to focus on current market conditions. In this particular case, you can see the re-plotted chart shows that KepDC fell into the buy zone at Good Value during the Feb/Mar correction giving investors an opportunity to pick up a high quality reit at good value prices.
KepDC is just one example, let's take another example to compare and contrast time horizons. Lets take a look at Mapletree Commercial Trust (MCT) Notice how the 5-year chart below shows that it corrected to the "Bargain" region during the Feb/Mar correction? Because of this chart, I picked up some positions in MCT in early April seeing that its trading at historically bargain prices. It was sold down heavily due to concerns of the Singapore circuit breaker measures that forced retail to close. However the markets overlooked the fact that its more than just a pure play retail REIT, its has a lot of office components as well unlike say SPH REIT or Starhill Global which is a pure play retail.
MCT has never traded into this range before historically.
Let's take another example of a REIT that has a long history, Ascendas REIT. Notice how the 5 year chart gives you a good indication of good value buy opportunities during the late-2015 and early-2016 and again during Feb/Mar-2020 correction? Notice now it also now hinting a potential sell with prices moving very close to the "Very Expensive" line? Hence if you are a longer term investor, looking at the 5-year chart gives you an idea of time horizons from peak-to-trough and peak again.
If you are a shorter term investor with holding period between 1 to 2 years, you could look at the 3-year chart. If you are a longer term investor with holding periods from 2 years to 4 years, the 5-year chart would be more relevant for you. So generally the different timeframes allow you to look at peak-to-trough durations based on your own time horizons.
There are special cases like KepDC REIT where historical data is less relavent today and therefore you would instead use a different timeframe.