Blue suits for men in the wedding party are the IT thing right now. I like them but it’s almost a cliche it is so common.
Doschicos, what shade of blue? Like royal blue?
My S asked his groomsmen to wear either grey or blue suits, no hue specified. He wore a blue suit that I would classify as steel blue…not as dark as navy with grey undertones. Female members of the wedding party (including the moms) wore a mix of long and short. This was for a 6pm Sunday evening wedding in September. Then again, it was at the zoo. Without a specified dress code, guests wore the gamut from long dresses to a summer romper, like those sundresses described above. Male guests all wore suits, even without direction. I hope everyone was comfortable - it seemed that ws the case. For the rehearsal dinner, though, I did put “casual” on the invitation since it was held in a hipster beer hall.
I think some do, but just don’t care as evidenced, as an example, by 11 (!!) seasons of Bridezillas. And no, I don’t watch it. 
Every man, IMO, should own at least one unless he’s in the military (in which case mess dress or service dress can usually be substituted as appropriate). One never knows when a wedding/funeral/graduation will pop up that requires one. If he only has one, it should be navy or charcoal.
In terms of wearing the same suit to back-to-back occasions, few notice what men are wearing. Regardless, changing the shirt/tie combo will make the suit look different. So if the man’s lifestyle does not warrant the expense of 2 suits, he can make do with one.
I’ll also add, it’s better to spend the money to get one quality suit altered to fit than buy 2 ill-fitting suits.
D1 had a formal wedding, but she asked men not to wear tux because she didn’t want them to look like waiters. I posted on another thread, she put on her wedding website of dress code for each event. She figured people could take the suggestion if they were stressed out about it or they could wear what they though was appropriate.
I don’t think a printed shirt with no tie is cocktail attire for men. I think a sport coat and slacks would be acceptable with or without a tie. It seems the intent of the couple is to have a formal wedding, so I would err on the formal side and add the tie for the cocktail attire event. For the formal event, a dark suit with white shirt and silk tie and dressy shoes - no rubber soles, would be best.
I quickly looked at D1’s wedding pictures again, and saw most men wore white shirt and solid color tie, a handful with very light blue shirt.
@bookworm I’d say navy to royal.
This is 4 years old but is still very much the trend, especially with the brown shoes.
https://www.weddingomania.com/the-hottest-2014-wedding-trend-30-navy-suits-for-grooms/
Yes, dark blue suit with brown shoes.
For the second time this week I am replying in a fashion thread with this beginning - “Maybe I am old-fashioned”, but I like to see a groom in a tux, not a suit. In the link above, some of those grooms look like they are going on a job interview. The couple looks uneven - she is in a spectacular gown and he is in a business suit!
I wore a very similar shirt to this one to a cocktail reception at a wedding recently, with a standard navy blazer and dark brown microfiber/cotton blend slacks. It was 95F and very humid outside and the venue wasn’t particularly cool, either! I immediately hung my jacket on a chair so I wouldn’t sweat like crazy. I would say that in the 40-60 year old male range, I was pretty typically dressed. The 60+ men were in suits and dress shirts without ties, the under 40 group were even more casual with shirts hanging out and some in dark wash (black, grey) jeans. So I was roughly middle of the road in a very varied group.
I would’ve paired the shirt with some awesome matching silk slacks from the same brand, but the ones I have are 10 years old and look crazy baggy now. The slim fit look on men has really slowly and insidiously changed my perception of how closely pants should fit these days!
https://www.tommybahama.com/en/Mercado-Stripe-Linen-Shirt/p/T319474-12755
God I hope that trend dies because the men in our family would not be caught dead in a blue suit with brown shoes. Mr. B would rather rent a tux than wear a “ready for retirement accountant’s attire.” 
"“ready for retirement accountant’s attire.”
It’s actually a younger look.
Personally, I think many tuxes are stodgy. Or many wear rented or cheap, ill-fitting tuxes and the shoes and accompanying gear and they look like they’re going to prom, IMO. Or like a waiter.
Or it’s not in keeping with the wedding style, venue, or time of day. Weddings, in general, are less stuffy and traditional these days.
^^^^^^ +1 to all of that for me!!!
A younger look that is recycled grandpa’s fashion. Plus, navy and royal blue are the colors reserved for the B and G’s mothers. 
B-)
Around here, suits are seldom worn—some very formal events, court, and a few very formal weddings and similar. Most events men are fine in a nice aloha shirt and khakis or similar.
Nope, not a fan the suits with shorter jackets, nor brown shoes with blue suit. The shorter jacket looks like the guys are busting out of their clothes or bought a size or two too small. H and I are not fans of brown footwear and don’t even own any. The contrast is too great to me. I prefer the look of black shoes with blue suits.
I love striped linen shirts and linen shirts. I love horizontal stripe ties. Not a fan of brown shoes and navy or cadet blue suits…it does look like someone couldn’t afford a different pair of shoes. Anyway I digress. I’m fine with Grooms and groomsmen in suits at a more informal wedding. That informal feeling is obviously alive and well these days. with more and more nontraditional venues and wedding themes. And even us olders who have gowns, cocktail dresses, suits etc. in the closet find it fun to go to a reception that isn’t terribly formal sometimes. No one I know seriously wears aloha shirts (except maybe to a Jimmy Buffet themed party - but we don’t live in Hawaii!). I’d say with our friends’ kids it is about 50/50 between the black tie formal weddings and the coat and sundress type weddings. Both are fun and it is so fun these days to really get dressed up once in awhile, even my H enjoys it.
While I personally would not either, this is one of those things to file under “Outdated style rules” alongside “Don’t wear white after Labor Day or before Memorial Day”
It’s funny, in my circles, men can wear aloha shirts practically everywhere—weddings, work, under blazers, theater, opera, funerals, you name it. Women on the other hand often agonize more about how dressy or casual and exactly what to wear.
Many of the men I know don’t own tuxes, H included. Our S does but only because he wore it for HS band. He’s loaned it out for a few proms to friends but hasn’t worn it since (tho still fits it over a decade later).
I don’t own any formal gowns as I have only purchased them to be a bridesmaid and donated them afterwards to HS for kids to use for proms. There is no where I’m invited where I’d want to wear a formal gown, with the exception of my kids’ weddings or someday perhaps future grandkids weddings if I care about attire at that age. My younger sister loves dressing up and does own and wear a few formal gowns and sparkling jewelry (I mostly store mine in safety deposit box).
Honestly, for females a nice solid color wrap dress in good fabric with appropriate accessories and wraps can take you about anywhere in our state.