It sounds like there may be a few things going on here. Either you're in a poor coverage area or your device is bogged down or possibly both. When I say bogged down it could be bogged down with a high demand for data or by a high demand for memory. With the former it can seem like you are in a low coverage area, so if you're sure you're in a good coverage area or you're on WiFi let's start there. Open your settings and go to data. Look there at what is using data, and what is using the most data. If nothing seems out of place there good, but if you notice some app that you barely open or use in the highest percentage of use you may want to limit its background usage. This will essentially cause it to access most of its background data over WiFi and as long as you don't notice any abnormal issues from this it would probably be safe to just leave it in this state. It will access data normally if you open the app or are using it so no fear that you're cutting it off. Anyway memory usage can create a laggy response in an app and it's not always the use in the app that is laggy causing the lag. You can go about this on your own but there are a lot of small apps that will clear your caches and free up memory. CCleaner is one, but whatever app you get avoid automated apps for this. They drain battery power, usually result in a few more issues than they solve, and it's not something that has to be done constantly, usually. You should be able to go in and clear your cache and get rid of junk files once a week or so to keep your device running smoothly, daily is too much, but you may find that it can be monthly and be enough. The other thing when it comes to memory that will bog you down is SMS. If you have thousands of messages, and hundreds of MMS you will notice a lag after some time. Keep a tidy in box and you may find that many of your issues will go away in all of your apps. If you're keeping things because you can't bare to let go, find a backup app and keep only those things you must have and let the rest go.