I skated in college through about Freestyle 3 or 4 (we didn't call it that then but I was working on loops and backspins, so I guess that's what it was).
And then I didn't skate for 17 years.
As have many of the people who write to me about returning to skating, I got back most of the old skills, and then some. (I'll never try a loop again. Lost my nerve.) When I started skating again I had weird deficits-- back crossovers were as strong as ever, but I couldn't do the forward ones to save my life. Those I had to relearn.
When I skated as a young woman, I never knew about USFSA (as it was then), there literally was no ISI, and I had no clue about tests whatsoever, because no one ever mentioned them to us. We just moved from skill to skill. So I started testing from scratch, as an adult.
Many skaters, however, come back to skating having racked up the tests, and want to know if those tests still "count."
Short answer-- yes. It's like your college degree. Doesn't matter if you got a degree in art and are now a salesperson. You still get to brag about the art degree. But first you have to prove you have the credential.
If you have an old ISI test, and can prove it (i.e. you have the paperwork), you're good to go at that level. However, until a few years ago when they went digital, ISI was farily notorious for its poor record-keeping, and it was hard to get proof of older credentials. I know several people who had to retest because ISI did not have their records (or the rink had never processed it).
If you want to compete now at a lower level than what you tested as a child or teen, you're in luck with ISI. Adult skaters over 21 years old can fill out an "Affidavit for Test Level" review and once approved, their test level can be lowered for what they can now accomplish. The skater or coach can request the form from the ISI office.
For USFS you always compete at your tested level, but they are Kind To Adults. There are several permutations that equal various levels of testing, and they divide by age where they have enough enrollment, as well as doing mixed levels. USFS is also less stringent on required elements than ISI for many events. See this post to learn more about adult competition levels.
Are you a returning adult skater? How close to your childhood level are you skating?