10 years old car with 145k on odo, it suggest that most of the part inside engine even if fine will create issue sooner, so it is better to spend some money and be in peace of mind, because cost of opening the engine and inconvenience of unavailability of car when it stands at the workshop for maintenance can be more frustrating. With engine overhaul you don't need to replace everything, like my car's clutch plate was fine so it was not changed, Also you can buy engine parts yourself to be sure of genuine quality and price.
I also learned it the hard way, i have a similar situation with white smoke and oil level decreasing, you should not run your car longer in this condition because it will do more harm to engine running on low oil levels.
How is the power of the engine ? Any heat up issues ? I think good mechanic can tell you after revving the engine and the sound it creates and the smoke it blows.