You can rent onboard, which is easier but then you have nothing to show for it afterward.

My advice is, buy one. You'll never regret having it. It doesn't have to be fancy, a couple of hundred dollars buys you the same quality as a rental, (in fact you can probably buy it at a rental place) including a formal shirt with pleats, collar style of your choice. If cash is tight, some rental places will sell rental stock after a few wearings. If cash isn't so tight, buy better.

2-3 rentals = the cost of buying the thing, and if you take reasonable care of it you'll never have to buy another unless you have a big weight change.

If you want to stand out a bit, buy a real bow tie and learn to tie it - my wife likes to do mine. Google the diagrams to learn to tie it. Avoid colours, classic black and white will knock them dead. Ordinary black dress shoes well polished are fine, I wouldn't be caught dead in patent leather shoes.

I've done two cruises with mine. I only take one formal shirt and wear it with a white undershirt, it's fine for the two formal nights on a one week cruise. Don't fool with a suit bag, just fold it neatly and hang it as soon as you get to your cabin. Wrinkles will hang out fine.

Why buy?

• you'll feel like a million bucks strolling into the dining room on the ship, as will your significant other if she's along.
• you can wear it to the night club after dinner.
• face it, the girls love it.
• if you're not married, you can wear it to your wedding when the day comes (in which case you might want to spend more on a nicer one.)
• you'll probably find one or two occasions a year when you'll wear it but wouldn't rent one. It's a nice way to stand out. Says something about you. Can also make a good impression on the boss depending on your job if you wear it to a suitable work related event.
• You don't have to fool with lining up to pick it up and return it on the ship.
• did I mention? the girls love it.

Sure you can wear a jacket and tie, but trust me, you'll look and feel better in a dinner jacket than a sports jacket.

Knock your self out - it's a great way to travel. We've done two cruises and can't wait for another.

By the way you're right about the age thing. We're in our 40's but act like in our 30's, and found a wide range if ages. Loved every minute of it.

Probably more info than you asked for, but there it is.