All these factors are important, and together determine the ability of a man to get his partner pregnant. Now, some man go for routine sperm count tests before they start trying to conceive with their partner. But let's face is, that is rather expensive and extremely rare. Normally, you would just stop using contraceptives and start living more healthily. When pregnancy doesn't happen, that can have all kinds of different causes, and oligospermia is just one of them. You don't know whether you have a low sperm count until you get a sperm analysis, something that you would normally do after two years of trying to get pregnant without any success.
Men who have been trying to conceive for a few months, or those who just want to boost their chances, can take some general steps that will increase sperm count and health. They include stopping alcohol and smoking (if you smoked in the first place), eating a healthy diet free of junk food, and taking a multivitamin just as your partner is probably doing. Keeping the testicles cool by avoiding hot baths, tight underwear, and laptops in that sensitive area helps as well. Finally, multiple ejaculations a day don't do your sperm count any favors. Having sex twice, three times, or even four times a week is fine. Every day is on the high side, and several times a day is really not good for your swimmers.