An SSD will speed up disc operations and boot.  How much on an older PC?? but it will still be noticeable.  If it were me, I would go with an SSD.  
Hi, My wife has an 580 MT Inspiron CPU is an Intel Core i3 Processor 530(2,93GHz,4MB) 8 GB of RAM onboard In 2016 we updated the Hard Drive to a Seagate 1 TB Hybrid. As it is the machine she uses for Business, that Drive could very likely be coming to its end of useful life. Money is very tight right now because of the Lockdown, so every cent counts. My question is, would replacing it with a 1TB SSD (Samsung 860 Evo, for example) show any speed improvements? Thanks in advance for any answers
Inspiron 580 MT Upgrade to SSD worthwhile?