Can I just replace the outsider condenser?

When I bought my home the Air handler was replaced but they didn't change the outside condenser unit. Is it okay if I buv a new condenser and have it installed?

I had some technicians out and they said I should replace both but why if the air handler is still newish? Included a pic of the unit; additional question what type of unit do I need to replace it (2/2) 1700 sqft? New to this sorry if that sound crazy