Should I Upgrade or Replace My Computer?
Upgrade when the computer is basically sound and one clear bottleneck is holding it back, such as an old hard drive or too little RAM. Replace when the processor is too weak for current use, parts are hard to justify, or several unrelated faults are appearing close together.
Upgrade when there is one obvious bottleneck
A computer with a mechanical hard drive is often a strong upgrade candidate, because replacing it with an SSD changes the part of the machine you feel every time it starts, opens programs or switches between tasks. Low RAM is another clear case when the computer starts out usable but slows down once several browser tabs, documents or apps are open. In both cases, the rest of the computer needs to be sound enough to justify the spend.
Replace when the whole machine is holding you back
If the processor is already struggling with everyday work, an SSD or RAM upgrade can only go so far. The same applies when the battery is tired, the screen is damaged, the keyboard has faults and performance is poor all at once. Several unrelated problems together are a sign the upgrade money may be better kept for a replacement.
Desktop and laptop decisions differ
Desktops are easier to upgrade in stages: storage, memory, power supply and sometimes graphics can be replaced without disturbing the whole machine. Laptops are more constrained. Some have soldered memory, limited storage options or expensive model-specific parts, so the same dollar amount may buy less useful life than it would on a desktop.
What I check before recommending either
The useful checks are practical: current storage type and health, memory capacity and whether it is upgradeable, processor age, heat levels, battery condition on laptops, and whether parts are readily available. That turns the decision from a guess into a simple value question: how much useful life does this spend realistically buy?