I use WIFI that resets every hour (Have to log in every hour)

[ultrasonicsite]

Is bitcoins useless for me?

[Strofcon]

From what I've been reading on the forums and the FAQ, it appears that BitCoin will simply pick up where it left off if the client is shutdown or can't communicate with the network.

In fact, it may even be that it will continue to calculate, but just won't be able to retrieve the most up-to-date information from other nodes, nor communicate out to those nodes. So if you forget to log in and stay offline for a while, then yea... you'd probably be hosed.

[laszlo]

You will not be able to generate if you're not connected.  Generation will stop until at least one connection is made and the most up to date block is received - it is a block chain after all so you can't insert links in the middle, you always are adding to the end.

[lachesis]

However, just because you can't generate doesn't mean Bitcoin is useless! Bitcoin is primarily about exchanging coins, not generating them. You can still send Bitcoins when your network is up, and your client will still get coins sent to you even if it happens to be offline when they are sent. When you download the newest blocks from other nodes upon coming back online, your client will get those transactions.