Switching to a new address after every transaction is not feasible because of the high transaction fees. Not to mention the transaction time.
I don't understand what you are saying here.
Why would using a new address for the change from your transaction have any effect at all on the transaction fees or the transaction time?
To reduce fees, you may want to consider moving your bitcoins to a SegWit address.
My reply was to what ranochigo wrote:
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.
I imported my private key to Electrum. When I spend BTC, any remaining BTC gets sent back to my original address. In effect, Electrum is reusing my BTC address as its default behavior for an imported private key. To move my remaining BTC to a new address would require a second transaction, which would incur a transaction fee (about $25 USD to $30 USD based on today's rate?).