At some point, every runner will ask this question. Although not an expert, I have experience and opinions that may help you navigate the decision.

Overall, I recommend coaching of some form – whether it be an actual coach, training plan, or training group. The advantages are significant – distillation of years of knowledge to help close the gap to your goals faster.

Below is a typical coaching trajectory you might consider:

1. Training Plan: Start coaching by purchasing a training plan from a website. The plan could  be a standard template or customized to your needs. Having a formal training plan is an ideal first step to add structure, tactics, and disciple towards achieving your goals. There are many options out there, but below are two I recommend:

• Sage Running™ - Coaches Sandi Nypaver and Sage Canaday are accomplished professional runners, social media contributors, and excellent coaches for novices to experts.
• Hanson Coaching - Professional running team that offers individual coaching plans and services. This is how I started my coaching journy. 
• Training Peaks – Sizeable collection of stock training plans for all distances and levels

2. Group Coaching:  Next, consider group coaching through your local running club or running store. Most have group workouts one or two days per week under the guidance of an experienced coach. The coaching is normally free (but you should look to support the organizations in other ways). This method is an approachable way to begin personalized coaching with the added benefit of running partners and weekly check-ins with a coach on your existing training plan.

3. 1:1 Coaching: Eventually, at some point, you will consider a 1:1 coach. I have a great running coach. Now, personal coaches come at a cost, but the value provided is numerous:

• Good running coaches set long-term goals (+2-3 years) and design training segments to achieve those goals. Normally, most runners look 3 months to the next race without a vision of where he or she wants to be long-term. Running coaches help you plan the macro while you execute the micro each day.
• Good running coaches push runners beyond the limits of what he or she thought was a possible. Coaches push their clients to new levels – levels that are physically possible, but mentally daunting. For me, I had struggled to break 3-hours in the marathon until my running coach made me believe mentally and then designed workouts for me to believe physically.
• Good running coaches can offer years of learning in a single conversation. Coaches have been around the sport and have seen what works and does not work. A runner that listens can use this advice to navigate more quickly to his or her goals.
• Good running coaches know when to provide a pep-talk or kick-in-the-butt. My running coach has a knack for applying a hard or soft touch before workouts or races – just when I am needing extra motivation.

Good luck to you all on your training! Whether you train by yourself or with a coach, I am always happy to listen, offer advice, or, if needed, that well-timed kicked-in the-butt.