Yeah, I admit it's lazy. I need to tinker with Electrum more. I imported a private key into Electrum-LTC and spent some LTC. For whatever reason, by default, after I spent a portion of the LTC, the Electrum-LTC wallet sent the leftover LTC back to the original address. I'm assuming if Electrum-LTC is a fork of Electrum, they both work similarly for imported private keys.
If you imported your address into Electrum, the default behaviour is to send the coins back to the origin address. They cannot implement change address since they aren't going to generate addresses without seeds for you. The reason for this is to minimise confusion.
That's why I was wondering what is the possibility that somebody can hack my address over the next several months if I reuse it. If the probability is extremely low, I don't mind the risk I take over the next several months, provided that at the end of my spending at the end of the next few months, that I move my coins to a new address and don't spend from the new address.
In your opinion, do hackers even have the technology or has a weakness in ECDSA been found recently such that reusing the same address over the next few months is susceptible to being hacked?
The current problem with ECDSA is that it is susceptible to attacks by quantum computer due to Shor's algorithm. This means that quantum computers can potentially crack ECDSA in a reasonable amount of time. However, the current progress of quantum computing is not anywhere near to the point for which encryptions are vulnerable to them. Even so, it may take some time for each address to be cracked.
Frankly speaking, unless you own thousands of BTC, no one would bother to try your address. It isn't free to use nor is it cheap and there are other things to crack than your BTC address.