Juan Foote

In regards to the theft issue.

I see a lot of folks here in town riding bikes that are mechanically sound, but visually ugly. Lots of stickers, spray paint, etc. All parts are bolt on, and when I see them locked up often will be using 2 or 3 locks.

MRT2

I read his book 5 years ago. I disagree with him on his opinions about gear. If you don't want to wear cycling kit, that is fine. But it does make the riding experience better. On the other hand, you don't need to look like some wannabe racer, or ride a full on racing bike to get out and enjoy riding a bike.

linberl

Your choice of locks will depend on the bike you got. If it is a beater, then a mini u lock or two would work. Get ones that lock on both ends, not the ones with the u shaped bar on one side. Onguard, for example, requires two cuts to get the off. Some of the kryptonite locks have the u shaped end so one cut is all it takes.
Mini u locks are better than bigger ones because it is harder to get a device in them to force the ends to pop out, a standard technique of thieves. Carjacks don't fit and getting leverage with a bar is harder due to the small space which is taken up by the bike and what you lock it to.
Locks mean nothing if you lock them to something weak, like a chain link fence or a pole or loose rack where they can take the bolts out or cut easily.
If the bike is reasonably costly, then you can also add in some wheel locks like pinhead or pitlock along with your u locks. Just makes it harder for thieves to take. Also you can secure your seat and saddle with things like Fortified Bike payback bolts, which come with a replacement guarantee.

Retro Grouch 

Hold your cell phone up directly above your head and take a selfie. Some people's heads are more oval front-to-back, and some heads are more perfectly round. Whichever your head is can affect which helmet will feel more comfortable.

mitmitenhp7

Wear some bright reflective vest when riding in the evening. Beware of pedestrians entering bike lanes without looking. And good helmet, it's very important. When I had choosed a helmet, I came across a useful article about helmets: Properly Chosen Helmet ? Halfway to a Safe Ride | Best Adviser
If you have your opinion about it, I would like to hear.

Jim from Boston

New to cycling, what are must have gears accessories and tips?+10 As a decades-long cyclist including year-round commuting in Boston, my singular reply to this complex and open-ended question is that.

Juan Foote

I would call that complete fallacy. Wearing kit makes you more aero. Beyond that, I "hear say" about the compression being good for your muscles and all that. I would imagine that IS true when riding long (long distances), but I see no advantage. Matter of fact, spandex make me uncomfortable in the groin and give me giant rash/rub issues with or without "butter" and all that other hoobaloo crap they try to upsell. Continued use over time causes even worse issues (for me).

I put on a set of "gym" shorts and ride comfortably, albeit a bit slower.

MRT2

Complete fallacy? Really? I would urge riders to make up their own minds.

There is nothing aero about me, with or without spandex. IDK which shorts you wore, so I cannot comment. What I can say is, once I went to cycling shorts and more importantly, chamois, chafing and saddle sores for the most part became a thing of the past and I won't ride more than an hour without it. As for cycling jerseys, it is true you can do almost as well with technical T shirts, but cycling jerseys are cut longer in the back, have back pockets to carry ID, money, phone, and extra food, and the zipper in the front is handy to added ventilation on hot days.

Juan Foote

Oh, absolutely. People are going to do what (they think) works for them.