Its always a risk. Its why Airline Miles are not the sort've thing you want to keep in your retirement account. Rather, use them whenever you can. My philosophy has been to use them, but try to keep enough for those occasional brass rings, e.g. when SQ upgraded their systems and released award tickets to alliance partners.

Its a balance... But, in the end, nearly everything gets worse... Its like the 'ole Baz Luhrman song says. "Accept certain inalienable truths, prices will rise, politicians will philander, you too will get old, and when you do you’ll fantasize
that when you were young prices were reasonable, politicians were
noble and children respected their elders. Respect your elders." .... I'd love to see $200 transcons again, and amazing mile redemptions for the LH A380 to Singapore, Tokyo, or elsewhere.

That said, it'd be great for airlines to not devalue their FF programs, or worse, transition to revenue based... But you have to enact reasonable risk mitigation techniques.

Just my two cents.