What is the best tool or function to compare data between two workbooks where the data is almost identical and I need to find out what is different between them?

I am a regular Excel user, but I am not particularly well versed in it. I am frequently given a workbook of assets and all their associated data (size, model, manufacturer, last repair dates, ID numbers etc.), separated into columns. ID number is usually column A. These lists are anywhere from 50 to 400 rows. My job is to bid repair jobs from these lists. However, it never fails that just as I complete this, I am sent an "updated" list to work from. I then have to compare the two workbooks to see what, if anything, has been added or removed. The second list is often in more or less the same order as the first one, but not always. My question is how do I most easily compare the data from the two separate Excel workbooks to figure out what was added/removed? I will take any course or tutorial that can cut this down from taking me several hours to under an hour. I just need to know where I should be looking