I think the main complaint some people had was what Viktor Petrenko did in the late 80's-early 90's where he had the same program for THREE years while the other men kept changing theirs.
Not all. E.g., Paul Wylie had used pretty much the same long program for three years also, but he had changed to a new one before 1992. And didn't Kurt Browning had the same one in 1989 and 1990?
Longer ago, some skaters would keep the same music (whole programs, or one or more personal favorite selections in programs with several contrasting pieces, as was typical in 1970s and 80s for instance) for even longer than that. Before there was television coverage of whole programs, or when even top skaters might be shown on television at most twice a year. Once the top skaters were being televised more frequently, there was more incentive to develop new programs. And more money available to amateur-now-"eligible" skaters to pay for music editing and choreography.
As a fan, I like to see skaters branch out in different directions and show different sides of themselves with different music choices. Of course, I'd rather watch a complex, detailed program many times, hopefully some of them skated especially well, than to see skaters change the music and costumes more often but pretty much do the same generic moves regardless, which is often the case. Just because a program is "new" doesn't necessarily make it less boring than an old one.
But I certainly don't think skaters should be required to change their music/choreography or penalized for not doing so at any predetermined interval.
Sometimes skaters dump a program that isn't working and get a new one mid-season, so the new program may not be trained and performed to its potential by the end of that season.
Sometimes skaters are injured or otherwise end up missing most of a season so few if any fans (and judges) get the chance to see the program, live or on TV.
In these cases, the skater may decide to get more use out of the program the following season as long as they spent the time learning it (and the money for the music editing, choreography, and costume). Or they may decide they're sick of it after practicing it for a year, even if hardly anyone got to see it, or it may have bad associations for them if connected to a bad year, and they want to move on. That should be their choice.
Some skaters happen to skate and place well at the events that get the most TV coverage, including short programs, or may happen to catch the interest of the producers and get shown despite mediocre placement, and others may be less fortunate in terms of media exposure. Some skaters get invited to and choose to participate in cheesefests or shows where it's appropriate to skate their competitive programs and the programs get televised even more often. This can also vary from one country to another, so that a certain program could be televised 6 times in one season in the US and never or only once in Japan, or vice versa, even if the skaters actually skated in the same number of events that year with comparable overall placements for the season.
Skaters at lower levels may keep the same programs for several years and never be televised or never qualify for events with large live audiences like Worlds, or Nationals in countries where skating is popular; if they finally do make a breakthrough their programs will be fresh to the fans even though the skaters have been using them for years.
Some skaters who are working their way up and don't have a lot of financial resources may decide to invest in one or two programs from well-known choreographers that can enhance their skating more than what their technical coach can devise, and then keep skating those programs until they get some competitive results that net them some money-making opportunities such as prize money and/or invitations to perform in shows.
Some skaters may keep each program for two years but alternate changing the short or the long each year.
Some skaters may go back to music they skated to years earlier and have always loved but change the programs as applicable to reflect new rules and new skills.
Some skaters just find one style they feel comfortable and stick to it, changing the music and costumes and choreography each year but with each remaining so similar that it may seem to viewers that they always skate the same program.
There are so many different reasons that skaters may use the same or similar programs for more than one year that there would be no really fair way to regulate it. The two-different-long-programs experiment at the Grand Prix Final a few years ago certainly wasn't very successful in treating audiences to more new, well-rehearsed programs from the top skaters.