A computer is [should be] being upgraded all the time, small upgrades generally referred to as patches. Patches come in many types, from driver upgrades and security patches to service packs and so on. The biggest upgrade is an upgrade to the next version of the operating system for example Windows 7/8 to Windows 10. These days, with Windows 10, the service packs can be significant but are generally worth it as they add a plethora of improvements and new features.
To Upgrade or Not to Upgrade
There are many reasons to consider upgrading; speed improvements, greater stability, general technical improvements, a more capable system and improved security against the many threats of the anarchic internet. There are also reasons to consider not upgrading your operating system... primarily the idea of "If it ain't broke, don't fix it" but also hardware incompatibility, low specification systems or that you don't use your PC for much more than email and surfing.
Practical considerations include the type of system you are running. Custom build PCs tend to be relatively easy to upgrade since they were built with separate components. Purchased desktops/small tower PCs can be more difficult as they are compact units or the manufacturers, for reasons of their own, have made it more challenging to do so. The compact nature of laptops limits their upgradeability and makes them difficult to disassemble while tablets and phones might be best described as "difficult".
But let's consider these scenarios and assume you actually do want to upgrade the storage (hard drive) and memory on your computer, how challenging would it be?
- Custom PCs: A modern custom-built PC might have 4 memory slots and be capable of supporting up to 32GB of RAM (4 x 8GB) so, if you have 8GB of RAM in one slot (1 x 8GB) upgrading it to full capacity should simply be a matter of purchasing and installing (slotting in) 3 additional 8GB chips. If you had 8GB in 2 slots (2 x 4GB) upgrading it to full capacity would mean buying 4 8GB chips and installing them though you would lose the 2 4GB ones you already have. Of course, 32GB is an awful lot of memory and 16GB would be a cheaper and more effective upgrade since that means buying only 2 x 4GB and filling the two empty slots. A custom-built PC can support many disk drives, sometimes as many as 8, so upgrading it might mean just adding another drive and configuring the PC accordingly. Upgrading the hard drive is, at least from a physical point of view, likely to be quite easy and even transferring the data should not present too much of a challenge if you have a spare drive (and custom PC owners usually do) which you can slot in to transfer data to. Or, of course, a USB external drive.
- Consumer PCs: Though they often have 4 memory slots, consumer PCs can be more challenging with respect to available room inside the case and possible difficulty in accessing internal components but there is, however, another factor. Consumer PCs seem rarely to be built from the same high-quality components that a custom build PC might be quite simply because those who build custom machines tend to be enthusiasts and willing to spend a great deal of money on a new system, understanding the capabilities and limits and making sure build the best one possible within their budgetary limits. Consumer PCs however, are often built from lower quality or bespoke components that make it difficult to upgrade them effectively. Accessing the hard drive or installing a second one might be similarly difficult although any PC system can usually access a USB drive to transfer their data to.
- Laptops and Netbooks: Laptops have a fixed screen, a motherboard and CPU that simply cannot be upgraded and relatively easy upgrades on PCs, such as changing a video card (or adding one if it doesn't have a better one) is close to impossible. Memory is usually limited to 2 slots and often in terms of capability ... you'll commonly find that a laptop might max out at half the amount of memory a PC can. Also, since laptops can only take a 2½" drive, replacing them will usually be more expensive. USB slots allowing (they are often more limited than a desktop), a laptop can transfer a data to an external drive.
- Tablets or Phones: Tablets and phones are almost impossible to upgrade in terms of memory or hard disc except that you can sometimes add an additional storage chip to give you more (separate) disc space. It is extremely difficult to back up data to a USB drive but many companies now allow backups via [often costly] cloud services.
A final consideration is that an upgrade might mean being without your computer for some time, anything from a day to a week and many people live considerable parts of their lives online. That said, many often have several computers, a desktop PC, a laptop, a tablet and a phone all of which are variously capable of doing some of the things they need done. Assuming all your various devices are reasonably up to date, it is unlikely that your phone or tablet can do the all things your laptop or PC can and whilst a laptop's primary advantage is portability and reasonable computing power a decent desktop system will still outperform it by several times.
In general terms, the bigger and more customisable your system is, the more capable and upgradeable it will be. The more consumer oriented and smaller a computer is, the less capable it will be, more difficult to upgrade and the more likely your upgrade path will have to be an entirely new machine.
Upgrades aren't usually cheap but they can be cheaper than buying a new system, there are issues to consider such as the time you may have to spend without your computer, data transfer and legacy issues with your new system (its compatibility with older programs). Upgrades can be worth it, they just need to be thought about first.