It's up to you. Outside is much harder because it requires more prep, patience, time, help, money and of course, effort. I have been painting my own houses and rental properties interiors for 20 years, and I painted the exterior of one, once. I then had it promptly done again by professionals who said it would have been cheaper if they didn't have to undo my work first. My advice is to get pros for the outside because everyone will see it.
Painters will agree that you should always aim to paint in the part of the year when it’s least likely to rain, has low humidity, and when the temperatures are above 50 F. Rain can wash wet latex paint off a wall, and temps that are too low can affect the way the paint sticks to the walls. Some painters will add additives to the paint if working in very high temperatures to slow down the drying time.
One important consideration when comparison shopping for interior paint is the manufacturer’s available palette. One brand of latex paint may be significantly less expensive than others, but the tint options can be limited. There can also be a noticeable difference between one manufacturer’s “midnight blue” and another’s “Prussian blue.” There is no universal standard, so this is why sample cards and test paints are so important.
Most of a projects price is the cost of labor at $25 to $75 per hour. However, most contractors bid out based on the entire project which includes all work hours. Hourly rates are only useful if your pro asks to do the job as “time and materials.” However, be wary of this pricing structure, it usually shows the contractor is uncertain how long the project will take.