Learn from the previous incident, when myetherwallet got attacked from DNS, so its better for us not to login to MEW account if its not important.
We can login to MEW if only :
1. Transfer, it can be TOKEN or ETH
2. Add custom TOKEN
Check the URL first, it should be
https://www.myetherwallet.com/ Make sure the site is using https://
There will be green lock icon in the left side of the corner web address. It writes MyEtherWallet Inc [US]
But if you want to check the saldo in your wallet, i recommend you to use etherscan.io
The reason of using etherscan is we get benefits which are :
1. It can check the transaction in and out to our ERC20 address
2. It can check the accumulation of our ETH and TOKEN amount in dollars (not all TOKEN has price)
3. It can make watch list, so if there is transaction, the notification will appear from email (must have account and login). 1 account etherscan can make many watchlist erc20 address, no matter it is in metamask, MEW, imtoken, and others as long as it uses erc20 wallet address
4. There is API KEYs facility (the developer must know the function) the further function i have not known yet... please for anyone who knows better about API, you can share