FFPs have tightened their belts considerably in the last decade or two.

There was a time when the average leisure flyer could pick up a few credit cards and take the family round the world in J every year. Those days are gone and they are not coming back.

That said, it is still worth collecting miles, certainly on spend that you are already committed to. I generally do not change my spending patterns solely for the purpose of collecting miles and points. But I do grab what I can if it costs me nothing.

As for redemptions, finding 2 x J-Class Super Saver seats to the exact airport you want, on the exact day that you want, with the airline you want is very rarely a realistic prospect. However, if you can fly a few days earlier, to somewhere vaguely near your destination, then fill in the gap, you're in business.

Hypothetical example:

Person A: I want to go to Rome in Business Class on Lufthansa on the 12th and come back on the 18th. Oh dear, no seats. These miles are useless.

Person B: Hmmm...TAP has a couple of J seats to Lisbon on the 9th. Maybe we could enjoy a couple of days there, then catch a cheap flight onward. Coming back is difficult...but LOT has availability via a one-day stop in Warsaw. Let's go for it.

Person A forks over $6,000 and complains that his miles are useless.

Person B enjoys three cities for less than the price of one.

My own style is to pick up the cheapest possible cash fares, get what miles I can from credit cards, etc, and use them to fill in the gaps. In the 6 years since I semi-retired, I have been flying all over the place on error fares and special deals, while using the miles to buzz around Europe for £17.50 and around the USA for $5.60.