It depends on your climate and cost of power. Wgere are you and what
do you pay for electricity? If your old unit is working fine, not
costing you a lot in repair bills and power bills are not biting your
wallet, I wouldn't bother changing it.

What you hear on talk radio is mostly opinion, not fact. (Mostly BS)
sometimes it is a commercial disguised as information

I am replacing my 16 year old heat pump this year. It has developed a
Freon leak in a place that can't be fixed. My power bills are $150.00
average. I will put in 18.6 SEER Lennox. My power bills should drop
to about $110.00. I will do my own install as I am a Lennox dealer,
and I will get a price break on the unit since it is for my own home.
I live about 6 miles from ocean, so corrosion is a factor. We pay 8
cents per kilowatt hour.

If I knew your situation I could give a better answer.

Stretch