I did contract work for several years in my career. It was a different job market back then (outsourcing was relatively rare, etc.).
I remember it, it was even a world in which people worked for themselves sometimes (in software etc.). You really don't see that very much now (in that industry, sure in entirely different things you do).

They also don't do long term contracts now as the government highly discouraged them and that I learned from my present employer (the government thought they were a way to avoid hiring full time employees - of course they were). So contracts seldom go over a year now and don't tend to be extended, once in a while you see a rare 2 year contract or something.

In contract work, you're very aware of when the contract ends and you're keeping your eyes open for the next job; it's shifting sand all the time until it happens.
I'm honestly not sure how that works, especially with a contract that doesn't last long to begin with. And they aren't always entirely sure of how long a contract will even last. No paid time off, so how to interview? Take unpaid time? Ok sure but you can't miss your ACTUAL job ALL THE TIME even if it is contract, to interview right and left and yes it looks even worse given you don't even have vacation or sick time (well very little sick time anyway). But that problem exists in a full time job if seeking a new one? To a degree. But you can take your time and space it out (depending on how desperate you are to get out) - there may not be some rush - must get a new job now! Also if you work somewhere that has paid time off and people are allowed to use it, it doesn't look bad to take it.

It worked out; my wife and I knew this could happen so we socked away a little of my income for the dry spells (that might be another difference from contracting today).
I will but being realistic, you can't sock away vast amounts of savings working a few months. If my life consists of working a few months a year from now on, I am in trouble

Contract work is in many ways a different animal than being a full-time employee. But it has some pluses if you're of the mind to pursue it.
It has some pluses, if I didn't feel so economically vulnerable, it would be highly appealing just for variety. But I come to it out of long term unemployment, and I don't see any reason that can't happen again, and it leaves me scared.

As for advancement:
1) old old rules: stay with a company for life - get the gold watch and the pension
2) newer but now also maybe obsolete rules (what my generation was told) - companies have no loyalty to you, have no loyalty to them, just think about improving yourself as a product, jump companies to advance yourself etc.
3) new rules: if you can actually manage to get a decent paying full time job, thank your lucky stars and hold on to it for dear life. companies still have no loyalty to you, and some day a pink slip or even training your replacement, but everything else is gigs and low paid work as far as the eye can see, ride the gravy train as far as it goes.