A reader, I'll call him "S," wanted to know if there's a hard drive enclosure that can "accept the thicker hard drive out of an old [laptop]."
I'm not sure what you mean by "thicker hard drive," S, or just how old a laptop you're talking about. But I can tell you that for at least the last decade, laptops have relied on 2.5-inch IDE (a.k.a. ATA) drives. Newer models also employ 2.5-inch drives, but with a SATA interface.
As for enclosures, you're on the right track: These inexpensive accessories are ideal for recycling old laptop drives that have been replaced by higher-capacity models.
An enclosure is essentially an external case for that internal drive, one that lends it a USB interface. When all is said and done, you'll have a compact USB hard drive you can use for backups, extra storage, transporting files, and so on.
More immediately, an enclosure lets you easily restore your data onto the new drive--a simple drag-and-drop operation. With that done, you'll have to decide if you want to wipe the drive or keep it intact (you know, "just in case").
When shopping for an enclosure, make sure to choose one that offers the proper kind of interface for your old drive. Again, if it's more than a few years old, it's probably IDE. Any newer and it's more likely to be SATA. In either case, you should be able to find one for just $10-15. I recommend hitting sites like Meritline and Newegg.
Hope that answers your question, S!