Now this is insightful. How can economists keep up when prices change all the time? For the large macroeconomic data like average home prices, average grocery prices, etc. inflation doesn't hamper observations because it is baked in. In fact, the primary way we measure inflation is to compare the prices of a selection of goods and services one year, to another year. The rate of change in prices is the inflation rate.
As for decision makers, say an economist or finance person at a bank, they aren't trying to study inflation, but trying to best against it. If those decision makers think inflation is going to be low, say around 2%, they will need to account for that when they set an interest rate for a loan. For example, if I charge someone 3% interest and the inflation rate is high, say 5%, if that person pays me back next year in full with the interest owed, I may have 3% more money, but that money is worth 5% less. As you can see, inflation are very important. Not just in that people have the value of their savings dwindled (anyone with cash in a savings account over that year can now buy 5% less as well, sorry), but also for people loaning money. That loan example I gave earlier means that the person who loaned money is worse off. We will talk in class (later) why that is a bad thing for more than just the bank.
As for decision makers, say an economist or finance person at a bank, they aren't trying to study inflation, but trying to best against it. If those decision makers think inflation is going to be low, say around 2%, they will need to account for that when they set an interest rate for a loan. For example, if I charge someone 3% interest and the inflation rate is high, say 5%, if that person pays me back next year in full with the interest owed, I may have 3% more money, but that money is worth 5% less. As you can see, inflation are very important. Not just in that people have the value of their savings dwindled (anyone with cash in a savings account over that year can now buy 5% less as well, sorry), but also for people loaning money. That loan example I gave earlier means that the person who loaned money is worse off. We will talk in class (later) why that is a bad thing for more than just the bank.