- slide 1 of 5
Depending mostly on the file format, compressing data can save space. As such, not all files can be compressed efficiently with the same ratio.
For example, a 1 MB PDF file will take the same disk space as a 1 MB text file, but the text file will provide better compression results because, unlike text, PDF already is a compressed file format. When compressing files, you can only guess the final space savings; you only know for sure how much space you save when the compression is complete.
Upgrading storage is the quickest route to gain space because packing and unpacking hundreds of gigabytes of data is just not worth your time in the long run. You'll lose countless hours in the process. Save your money, buy one of those terabyte hard drives, and be done with it for years (or maybe months, if you're constantly topping your monthly bandwidth and recording HD programming, for example).
Advantage: upgrading storage.
- slide 2 of 5
With a program such as TrueCrypt, you can easily add encrypted volumes to your system when you're upgrading your storage. This option restricts access to all files on a specified volume, not just a few archives. You can decrypt files and gain access to them only with the correct password, keyfile, or encrypted key. These are extremely effective measure in case of theft.
You can even add more protection by password protecting the compressed file archives, and by splitting those archives in multiple parts that you can save in different locations. Split files are easily joinable when extracting them from the archive.
Advantage: data compression.
- slide 3 of 5
Long term archiving
You need to trust that your storage device will give you the files you want when you want, without problems. That is especially true for important, though seldom accessed data, such as tax files. The last thing you want is to get a CRC error on a file archive that contains such files, and that can't be repaired, thus making the compressed files unusable.
Sadly, data compression increases the chances of such problems happening. It doesn't just add more protection to your files, it also adds another way to for them to get corrupted. The more files are compressed, the more they are altered, hence increasing the data corruption risk. When just upgrading your storage device, the files being saved on it for archival purposes should not be altered, save for human error or storage device failure.
Advantage: upgrading storage
- slide 4 of 5
Although prices for hard drives have fallen dramatically in the last few years (you can now buy a 1.5TB drive for less than $200), they still can't compare to the lowest price of file archivers: $0. There are plenty of good ones among the freeware, my favorite being 7-Zip.
Advantage: data compression
- slide 5 of 5
Although there's no clear overall winner here, we can see that each option answers specific needs. If you're someone who does a lot of file transfers, who doesn't need to keep data for very long, but wants to make that data as secure as possible, then compressing and optionally encrypting your data is for you. Otherwise, if you want to easily access the most space possible for long periods of time, I recommend upgrading your storage.