That is generally true.
I don't do anything special, except don't let myself get too tired and if I start sneezing incessantly and get a headache, I treat it right away.
I had pneumonia in high school, back in the day and then again, in 2004. I had gone on a weekend bike trip in Vermont that was very strenuous. It was October and very cold. I had started the sneezing a day or two before the trip, but I ignored it. About ten days later I went to the doc and yes, I had pneumonia. While I only stayed home from work for 2 days, it took me at least 6 weeks and 2 rounds of antibiotics to really get better. My cycling season ended about 6 weeks early.
I suspect I also had pneumonia as the result of the only time I had the flu, in the 90s. I had a 104 degree temperature and was horribly ill for 5 days. The coughing starteed when the fever broke and it took 8-10 weeks to get better, even with antibiotics.