Question Is it worth upgrading my laptop

[shadow8378]

I have a Asus Notebook X550ZA upgraded to 16gb of ram and it's still a little on the slow side is it worth upgrading to a ssd a better cpu or should I just sell it and buying a new laptop if so how much should I sell it for its about 2 years old the only damage is a few scratches from my cat on the corner

 

[SchizTech]

First, in modern laptops the CPU tends to be integrated (soldered on to the motherboard). In what way(s) is it slow? What do you do with it? Has it always been this way? Depending on what frustrates you specifically about it an SSD could help but we need more details.