You can attack and be attacked by all other players, most of them with more and bigger mechas, so at least in the beginning you should get xp. When you get enough xp you gain a new lvl. At some levels you are allowed to buy bigger bases (allows you to field more mechas), bigger mechas, and better weapons. You can buy all the equipment you want at all times (provided you have the resources), but equipment is tonnage based, so you can not put say a betrus processor on a Red Ant.
When you gain a lvl you can also upgrade your mechas. Basically you pay some ferrite, bioptics and generally crystal or niodes. Then you wait for a while and your mecha is upgraded. At some lvl your mechas will get new equipment and/or weaponslots, at all levevls you will get some more armor. You can also (if you have upgrade kits) instantly lvl 1 mecha once a day. If you have the niodes to burn you can also instantly upgrade a mecha 1 lvl for 5 niodes. Personally I use my niodes on other things, and try to use only upgrade packs to lvl my niode mechs.
I would recommend upgrading bases at every opportunity, at least up to lvl 20, after that you might consider whether the price is to high, and wait for the next available base. As for mechas, you can have as many as you want, but you can never Field more than your base allows you. So you might wonder why you should have more mechas?
Reasons are as follows - You will have upgraded mechas ready when you get a bigger base.
There are different events where you need different mechas. Your starting mechas will be outclassed by the opposition.
Submitted by Sten Hugo Hiller#627184