Quote from: cryptoking555 on December 31, 2017, 06:38:34 AM

I have also read that the more you reuse the same address to send BTC, the more your address is susceptible to being hacked.

Untrue. Unless your wallet generate keys with reused R values, it is safe to say that your BTC is safe for the time being.

Quote from: cryptoking555 on December 31, 2017, 06:38:34 AM

So let's say I am using a public address. I send a portion of my BTC from my public address to somebody else but the leftover BTC remains in my public address (doesn't Electrum keep your leftover BTC in the same address by default?).

Depends. If you generated the HD wallet in Electrum, Electrum will automatically send the change to a new address. The other unspent inputs remain in the address unless you change your settings.

Quote from: cryptoking555 on December 31, 2017, 06:38:34 AM

I use this same public address to send BTC from over the next several weeks. In total, I have sent from this address 4 or 5 times over several weeks. Several weeks later, after I am done sending my BTC, I backup my wallet and my private key, uninstall Electrum and decide to let my leftover BTC sit there in my public address.

With today's technology, how long would it take to hack this public address? Is this something I don't have to worry about for the next 10 years? The next 5 years? The next 1 year?

With todays technology, it would be infeasible to crack ECDSA (way more than 10 years). It might change with quantum computing though. You don't have to worry about it. Due to some circumstances, I was reusing my previous address for 3 years with upwards of 700 transactions. Nothing has happened yet.