For about a year and a half starting in September 2008, I rode my bike everywhere. I was very into it, in a retrogrouch way. Over time my knees started hurting so I stopped biking. I just tried coming back to it, easing into it so I don't hurt my knees again, and I was surprised at how many things were different:
Bike lanes: my old commute had no bike lanes. Now there are bike lanes almost my entire way. I'm in a slightly different place, biking West Somerville to Kendall instead of West Medford to Fresh Pond, but (a) if I did my previous commute now there's a mixture of bike lanes and a bike path and (b) the bike lines on my new commute didn't exist ten years ago.
More bikes: I didn't used to run into other bike commuters, but now when I stop at a light there's a whole line of us:
Helmets: I got a new cheap helmet (this one) and they've gotten much better. They're easy to adjust to fit, and they stay adjusted. It's possible that fancier helmets like this were around then, but now it's even the cheapest ones.
My work has showers and a bike cage. Possibly this is just me working at a fancier place now?
The biggest thing is that I'd forgotten how much I enjoy biking. It's just really nice, moving along under my own power, being able to go wherever I want, enjoying the sun. I'm pretty much the slowest bike out there, but there's enough traffic during rush hour that I'm still faster than cars, which is also a fun feeling. I don't know if my knees will be up for this long term, so I'll still take it slowly, but I'm happy I decided to try coming back to it!