Yes, if needed. Generally the rule of thumb is to try the maximum dose or maximum tolerated dose of one group and then combine the second tablet from a different group so that they can work together. But now-a-days we are using combination tablet even from the beginning.
Do they have side-effects?
Every medicine available in the market can have side-effects, so does Diabetes tablets. It is very important that you tolerate medicine, because if you do not tolerate you can not take them for a long time. If you have side-effects, you must make sure that is due to the tablets before stopping. Interestingly, some of the side-effects like indigestion, belching, loose motion with Metformin group of tablet disappear over time, so they should be started with a small dose to get adjusted with your system. Once adjusted, dose can be increased.
Once started, do I need to take them for life?
This all depends on your Diabetes. If your Diabetes is very well controlled, you may try only with diet. If that is fine, why not to control your Diabetes only with diet and life-style measures. But if you see, your control is not good with diet alone, you must accept that your body needs medicine and you should start again. Remember, there is a genuine chance, over the time your requirement of medicine is going to go up as type 2 Diabetes worsens with time.
Initially I was controlled with tablets, but despite doing the same things my sugar is uncontrolled?
This is very common question we face in our daily practice. The reason for telling again and again is that modern research established clearly that Diabetes never remains the same. The time for this worsening is different for different people. This is neither a fault of yours nor your doctor"s. If you have looked after yourself very well, it is very likely Diabetes will worsen slowly and the opposite is true as well. So, if you find despite doing the same thing your control is slipping, you should modify the treatment.