Can I charge my android cell phone with another usb chager? I have an Android phone and a Tablet. Sometimes, when traveling, I just want to take one of the chargers. Is this ok?

Can I just use any usb based charger in any android phone or tablet or can there be differences leading to issues in battery life?

Although there are several questions about this here, I didn't see the situation where one uses a charger with a lower intensity to charge an equipment that is supplied with a charger with higher intensity.

Another thing that may happen (I ask) is if there are some flavors of Android refuse to charge when the wrong intensity is given?
The basic answer is that any charger with the right connector should work, so basically you should be able to use either charger with either device.

But note that in order to charge the battery, the charger has to provide power to both the device and its battery.  For this reason, some devices will need a more powerful charger (e.g 2A or more) in order to be able to charge the battery.  Furthermore there are ways for the charger (and cable) to indicate to the device how much power it can provide (since, according to the USB spec, a device is not allowed to consume more than 0.5A, and even for that it first needs to negotiate it), so some devices will not use up all the power provided by a charger simply because it lacks the indication (from the charger and/or cable) that it can consume more.

This is a fairly murky area, in my experience, but the rule of thumb is that the charger of your more power-hungry device will usually work for a more frugal device, while the reverse is not necessarily true.