I prefer two middles and unless my future husband, whoever he may be, has serious issues with it, though I’m not sure why anyone would, my children will have two middles. I just prefer it and it means I can use more names that I love as well as using honouring ones.
For me, it’s simple: the more names, the better. I do think the palatability of two middles really depends on the combo, though.
Some people just love too many names or have multiple people they may want to honor in their family, so I get it (having more than 1 middle). I would limit my children’s names to just one though, just personal preference!
I think it really depends on the name itself.
It depends on the names but I’m really surprised - no, shocked - that any name nerd here on this site would think that two mn’s sound pretentious. What? We all [name_f]LOVE[/name_f] names, don’t we? That’s why this site exists in the first place. Two mn’s ARE NOT pretentious. Sometimes we love too many names that we need to exercise our right to give our children as many of our favourites as possible :). Let’s get serious now. What about [name_m]Roman[/name_m] Catholic children who are given one mn at birth by their parents and then when confirmation time comes along that child decides to take a saint’s name as their second mn? Is that child pretentious? I don’t think so. There rant over. Here are my rules (eg. general guidelines) for one or two mn’s.
1 If you have a common surname like [name_m]Smith[/name_m] or [name_m]Jones[/name_m], two mn’s are fine. The more names you have the less likely that any other [name_m]Smith[/name_m] or [name_m]Jones[/name_m] will get mixed up with your name.
2 If you have a rare or relatively long, difficult to spell and pronounce surname and you are not religious at all, one mn will suffice.
3 If you’re a religious name nerd (me :)), you have every right to choose two mn’s and not be labelled “pretentious”. There now, isn’t life beautiful? 
I would only use 2 middles to honor more family. Usually two middles are hard to flow, but if I find combos I really like, I would use 2.
I say two because I have two middles myself and I love it! Theres so much more you can do with extra names.
I have to say I like 2, my son has 2 middle names - he’s [name_u]Jude[/name_u] [name_m]Andrew[/name_m] [name_m]John[/name_m] & I’m due to have my second child any time & they will definitely have 2 middle names, for another boy the middle names will be [name_m]Henry[/name_m] [name_m]Jerome[/name_m] & for a girl it’ll be [name_f]Adelaide[/name_f] [name_f]Elsie[/name_f]. Now we just need to pick first names lol! I just love too many names to limit to one middle name…
I agree that it depends on the name and if you are honoring a family member. For instance, I recently saw a [name_u]Rory[/name_u] [name_f]Katherine[/name_f] [name_f]Elizabeth[/name_f]. I’ve always loved [name_u]Rory[/name_u] and [name_f]Elisabeth[/name_f]; I love the combo. I’d really like to honor my grandmother, [name_f]Esther[/name_f]. I’ve been really thinking about [name_f]Lucy[/name_f] [name_f]Victoria[/name_f] [name_f]Esther[/name_f], but I’m not sold on two middle names…
Sometimes I do like the way 2 middle names sounds, but generally I prefer just one. It’s simpler, less of a mouthfull, and generally just sounds better to me in the way the name flows.