If you're an intermediate or advanced student, you should start becoming comfortable with a more diverse range of vocabulary. For example, instead of saying "sometimes," why not say "every now and then"? This is a common phrase, and it is used by native and non-native English speakers around the world. The time phrases below fall into the same category.
3 ways to say "sometimes" (use at the start or end of a sentence)
every now and then (or "Now and then")
"Every now and then, I go for a walk on the beach."
from time to time
"I talk to him from time to time."
now and then
"We get together for coffee now and then."
Another way to say "always" (use at the end of a sentence)
all the time
"He drives the kids to school all the time."
Another way to say "rarely" (use before the verb)
"We hardly ever get together anymore."
I hope you will start using these phrases today, or that you will be familiar with them if you hear them in future conversations. Good luck!