Reasonable/safe for me to do a 30 minute workout every day?

If you're only doing cardio and you don't feel really sore the next day, I think it should be fine. But it won't be the end of the world if you take a rest day. Just pay attention to how you're feeling and take a day off or lower your intensity on some days if you need to.

You may not need a day off from *any* exercise, but it would probably benefit you to rest the muscle groups you've been working so hard (lower body). You could try an upper-body-focused workout from YouTube, for example. Or you could take an "active rest day", where you do an activity that uses your muscles less intensely -- example, a long walk at a comfortable pace, or a leisurely swim, or some flexibility-focused (not strength-focused) yoga. Active rest can, in many cases, speed recovery.

If you like biking, and are biking outdoors (I can't tell), you could choose a challenging route some days, with hills and an effort at speed, and bike more gently, on even surfaces, with more gliding, on your rest day.

Your muscles build during rest, so it's pretty important. But that doesn't mean you have to sit around the whole day!

Doing the same exercise every day won't be as beneficial as mixing activities as you'll only be working the same muscles each time.

I wouldn't think 30 minutes of easy riding would require a rest day. Rest days are important but you have to put everything into context...the more you're doing and the greater intensity to which you are doing them will determine how much rest you need from that activity.

I pretty much cycle for an hour every day and average about 75 - 80 miles per week and I lift 3x weekly...I need a rest day and usually take in on Sunday. My rides are generally varying degrees of intensity from sprints to big climbs, to nice flat speed rides etc.

But even on a rest day, I'm pretty generally active...I usually take the dog for a walk (about 3 miles) and then I have my outside chores like mowing the lawn and pulling weeds, etc. In the late mornings and afternoons we take the kiddos to the zoo or aquarium or botanical gardens or for a nature trail walk or to the pool, etc.

People have this notion that taking a rest day means you just go sit on your *kitten* and do jack ****...it can be that way I suppose but certainly doesn't have to be. A rest day is just rest from vigorous levels of effort for which your body needs recovery.

We are talking about only thirty minutes a day. I'm not knocking that--thats great-- but with under an hour of working out a day, you are unlikely to be at risk of overtraining or injury. If you do feel sore and tired, by all means, take a rest day. Listen to your body.

Before I ran my first marathon, I was overtraining and wouldn't listen to anyone who told me to stop-- but I was doing 10-13 miles a day (1.5-2hrs running) and got stress fracture. I've since smartened up and train smarter, not harder and have run 7 marathons thus far.
You need to keep in perspective what you're doing and how you feel. One good measure I was given--if you resting heart rate goes up ten beats or more and you feel tired a lot, take a break.

The "rest day" is primarily for weight training. You want to give your muscles time to heal before working them hard with weights again. There is nothing wrong with doing cardio everyday. Especially if your cardio consists of 30 minutes on a bike, it's fine.

The rest day is not primarily for weight training, it is primarily to keep people from overdoing it. If you run every day, you better believe your body needs time to recuperate.

That said, OP, you may not need a rest day now or at any time soon, but if one day you wake up and feel like a day off would be helpful to your body, take the day off.

Yes.

I walk every day for a couple of hours roundtrip. you dont need a rest day unless you are training super hard in my oppinion